Sony port so few games because the Sony sheep are so grateful for any PS1 release or remaster to justify spending 500+ on a console that constantly failed to deliver.
The Linux on PS5 hack makes the console a tempting platform for the RPCS3 PS3 emulator. Digital Foundry discovered that more GPU-dependent games thrived on the newer hardware. Unfortunately, performance suffered with titles designed to maximize the PlayStation 3's cell processor.