Onrush was a weird beasty because it looked like it was meant to be a racing game, but it was a combat game in racing clothes. I think the reason it did so poorly is that what it even was, was never made clear to the general public. So it was viewed and judged through the wrong lens.

In the datamined PS Classic list there were some greats... Crash Bandicoot, Gran Turismo, Kula World, MediEvil, Parappa the Rapper, Ridge Racer - hell, half of those are represented in PlayStation All-Stars Battle Royale. Some of the choices on the PS Classic seem really odd.

T-301: I think you're oversimplifying on the code thing...
When people were shuffled on from their studio disbanding, they were almost certainly prohibited from taking intellectual property off-site as individuals. At that point it's in Sony's care, and it would then have been shunted from pillar to post in various archiving and clean-up processes until it was so buried that nobody could find it anymore. I've seen it happen in my own workplaces.
It gets put on fileserver A, everyone gets migrated to fileserver B, not all the data gets moved across. A final archival backup is done of server A, it's stored on server C somewhere, but years go by and the new version of the backup software isn't compatible with the archive format that was used 15 years ago. IT in general is a goddamn mess, and we're talking about files that are old enough to buy alcohol.