Question about developer philosophy

We're preserving the console, not the specific games. Work on preserving the PS3 game library is being done by projects like Redump and No-Intro, and the vast majority of the library is already preserved. Blu-Rays also last a lot longer than CDs and DVDs so there is still a lot of time to preserve what's left as far as physical games go. As long as the games are preserved, it doesn't matter how much time an emulator takes to get to a state that can play it, because it's already successfully preserved so it's only a matter of time.

Furthermore, general improvements will eventually make these AAA games work. These games already have special attention anyways because they have the most people testing them and making bug reports on top of them. You can't expect an emulator in Alpha to just be running the most demanding games of the platform. If you have an emulator that runs all the demanding exclusive games but not the vast majority of simpler titles then you're doing something very wrong (very bad hacks).

There are also some advantages to debugging the emulator with multiplatform games with a PC version, you can compare the graphical output for example and try to find bugs in the RSX codepath, even though the games are not exactly the same. Also, there are many reasons why someone would want to play a console version of a game over a PC port. For example on LOTR Conquest, the disc of the PC version is rare to find (was sold by a short period of time) and it was delisted on Origin short after releasing, and the PC version does not have any of the DLC that released in console. On Minecraft, the game is different than the PC version and allows for native multiplayer splitscreen, which is something surprisingly requested a lot.

Most developers aren't even interested in any PS3 exclusives in particular (I've only played like 1 AAA PS3 game myself), but instead on the challenge of emulating and preserving the platform. This doesn't mean the games won't be preserved, they will, but no one is going to rush a bunch of hacks to the emulator just to get all the AAA working perfectly first and complicate development.