First off, RPCS3 *cannot* run all PS3 games. Roughly a third of the games on the compatibility list either can't be finished, have serious glitches, perform poorly, or cannot be played at all. Literally nobody has achieved perfect emulation of this 15+ year-old platform.
Next: yes, there was pushback on closing the PS3/Vita stores, but it was easy for Sony to change course on that because they literally didn't have to do anything. The only difference is that they didn't close the stores. For Sony to invest in proper PS3 emulation on PS5 would take a whole lot of time, and therefore, money.
The only way to convince Sony that this is a good idea would be to demonstrate some sort of tangible benefit. As in, if you do X, you can make Y amount of dollars by selling Z. Already, it is impossible to gauge how much the Xbox BC strategy has benefited the platform; yes, it is popular among fans; yes, it bolsters both Game Pass and Games with Gold; yes, it preserves customers' past investment. But you can't say that it has made Microsoft some specific, tangible amount of revenue.
Further, if you look at the list of million-sellers on PlayStation 3 (
link), you'll see that there are 37 games on it. Over half of these have already either been remastered and/or remade on PS4/PS5, or are currently available on modern Xbox platforms via BC, Nintendo Switch, and/or PC. As for the other games on the list:
- 3 of them are old Gran Turismo games. Old racing games with licensed cars almost never come back once the licenses expire.
- Metal Gear Solid 4. Konami's been repackaging their back catalog at a pretty good pace these days. I'd like to think this one will eventually happen, especially since folks would no longer balk at what will certainly be a huge download.
- Abandoned Sony properties like MotorStorm, inFamous, Resistance, Killzone, Heavenly Sword, and LittleBigPlanet. If PS3 BC were already a thing, it'd be worth it for them to throw these on the store, but Sony certainly would not invest in PS3 BC just for these.
- Ratchet & Clank Future. See above.
- One Piece: Pirate Warriors. This series is still running and is now multiplatform.
- God of War Collection, which includes the first two God of War games originally released on PS2. These could very well show up on the new service.
...and that is all. You may remember that MS is no longer adding games to their BC catalog, and that they specifically said it's because the remaining games--and there are many!--would not be worth the investment/effort required to get them added...and even as someone really disappointed that those games aren't there, I admit that they're right. My guess is that Sony looked at what has already been remade/remastered, and made this same determination for the entirety of the remaining PS3 catalog. Once they can no longer keep the PS3 farms running for streaming, these games will simply disappear. It sucks, and it's sad, but let's face facts here. How many folks are really going to subscribe to the Plus Premium service--or if it's an option, outright buy digital copies of MotorStorm or Ratchet & Clank Future--just because they'll run natively?
And for all you folks holding out for 3D Dot Game Heroes: don't. It never got a digital release, and Sony is in no hurry to let you use discs for BC. Heck, to this day, both PS4 and PS5 do not even support the playback of CD or CD-ROM discs, which means the entire PS1 library and many PS2 games cannot even physically be read by the drive. (
link)