The news was out there since a few days that Playstation in going to close down on PS3, PSP and PS Vita support. Now it seems that the news was quite valid and Sony has pulled down all the games for these consoles from their official website.
Sony Playstation store has been going under quite a few changes. Mostly being geared towards selling PS5 related items. Even the theme of the store has been changed to a more PS5 oriented color. It would seem that Sony isn’t gaining a lot of profit from keeping the older gen games alive on the store and wants the attention to shift towards the future of gaming.
If you are still looking for games related to PS3, PSP and PS Vita consoles there are many other creditable outlets out there in the shape of third party venders and also ad sharing websites. But we cant really hope for much if we still want to buy those games directly from the PSN store.