To be clear, while this is a bit of devil's advocacy, I'm not here to defend PlayStation. Their move to kill physical media for PlayStation before even announcing the PS6, much less releasing it is PS3 reveal era of Sony arrogance. Remember when they took the piss out of Microsoft for initially planning to make discs irrelevant with the Xbox One? Now Microsoft is testing a system to let you get free digital licenses from your disc games. Only in this industry can players so quickly switch from hero to villain and back.
I understand the value of physical media better than most. Should you have doubts, I invite you to observe and be humbled. I also have a top 1% Steam account with over 3,500 games in it, and that's not counting other PC digital purchases or the many on consoles I've made.

Having one foot up to my hip in both the physical and digital camps gives me a unique amount of insight into both and while I think this is a dumb thing to do on Sony's part (especially right after stealing back over 500 digital movies people paid for) and I understand why people are upset, I think it's important for those concerned about ownership and preservation to understand why discs don't mean what they used to and how this was ultimately inevitable.
Let's be real here, the vast majority of people screaming about this are just latching onto the latest Internet outrage trend like always. Most of them don't buy many or any physical games and most probably don't even own the PS5 with an optical drive. Big companies don't make decisions like this without a lot of data behind them and Sony's data is telling them that people largely don't want physical any more. The writing's been on the wall for two console generations and much longer on PC. GTA 6 is digital only and is estimated to have made $1 billion in the first hour of pre-orders. If y'all wanted discs to survive, y'all should have bought more of them.
I get the desire to have something tangible to signify ownership but in the all-digital age we're now in, the discs you have bought since the Xbox 360 era have been little more than symbolic. Virtually every physical game needs a huge patch--on day one in most cases as so many games ship broken or unfinished now--and many discs come without the complete game on them. This isn't like the old days when you put the disc or cartridge in without the Internet and everything just worked. When your platform's servers go down--and they all will one day--it's little more than a coaster.
An exception is the boutique industry that puts out physical editions of indie games, often months after release when they've been patched up, theoretically eliminating the need to be online. It sucks for them and their customers but many of them said they knew it would come one day and hopefully they have other ways to entice buyers. Not being scumbags would be a start. But that's the thing, it's a boutique industry, where releases are often sold in quantities of as little as 1,000 units, the minimum order Sony requires. It's a niche within a niche and while it's a valuable one, you can't expect Sony to keep producing optical drives and discs for that. Again, if this is as important as the protests claim, y'all should have bought more discs.
Resale is another valid argument and I too remember back in the day when I would buy a game, finish it, trade it back in for a fraction of what it was worth and partially fund the next one. The industry has had it out for the secondary market forever. But with digital purchases now firmly in the majority, what do you think I'm going to say? If being able to sell your games was so important, you should have gone to the store more. In a just world, we would be able to detach our digital licenses from our platform accounts and sell them on to someone else. We should also have the right to refund games within a certain amount of time as digital purchases are just bits being shifted around. The technology is there to make both trivially easy (Steam already does the returns thing, though not willingly) but we live in a world where corporations run everything and we're too lazy and disorganized to make politicians legislate for us and not them.
On preservation, I'm not going to even attempt to take a devil's advocate stance. It's just straight bullshit up and down. The industry has a duty of care to make their products available to preservation organizations and furthermore, should want to help preserve the art that they create. Like digital resale, the technology exists to make such things easy to do while still having measures to prevent and track the source of leaks. This should be accompanied by copyright reform that explicitly allows and requires such things but entertainment industries and their crooked lobbyists don't care about art and only see preservation as a potential threat to theoretical future profits, especially with how selling the same games over again has become common practice.
At the end of the day, buying a game on a disc doesn't mean you own it or are entitled to any added benefit than if you bought it digitally. I'm not saying that's the way it should be, I'm saying that's the way it is. We have collectively made it clear to the industry that we value convenience, instant gratification and always having the new shiny more than ownership, preservation and freedom. I include myself in that because for all the physical games I own, most of my new ones are bought on Steam. We're getting what we asked for and the industry knows those who truly care about this and aren't just outrage hopping are a very small number.
So if you're one of those few, what can you do? You could lobby for Sony to do what Nintendo has, continuing to produce physical copies but charging $10 more for them to cover the extra costs. Sony could also license another disc manufacturer to produce PlayStation discs if people made enough noise. Honestly though, I don't think discs are coming back and even if Sony reverses course for now, there won't be a Blu-ray drive in the PS6 or the next Xbox, count on that. They could implement their own version of Microsoft's Disc2Digital as well and I do think that's possible with enough demand, especially if people make use of it when it launches on Xbox. If you don't make it clear that you won't buy a PS6 without it though, don't expect them to care. Your money is all they want and you have to be prepared to speak with it.
Aside from just buying discs while you still can, I would consider supporting emulation projects, even if you don't use them at the moment. When these consoles and their servers are long dead, the emulation community and their passion is what's going to keep these games playable. There are amazing developers out there doing this work for free and they should be encouraged at every opportunity. Amplify and donate to preservation groups as well so they have a greater voice with lawmakers and can hopefully make some headway in getting preservation a legal framework like it always should have had.
Most importantly, don't just bitch impotently on social media, contact Sony and tell them why this matters to you. One direct email from a passionate fan has the weight of thousands of angry tweets and YouTube comments because it shows you care enough to make an actual effort. I've already done so and told them I'm not buying a PS6 if they continue down this road and I mean it. You'll get a generic form letter back but if enough people do that, Sony will take notice. It's happened before, it can happen again.
Games may be entertainment but they are also art and it's important players fight for that. Companies are about money and the single biggest way you can get through to them is to threaten to take yours somewhere else.