[makin]

There isn't much incentive in making new stuff when it can be shut down by Sony or whatever company at any moment. See A2MR.

[pjmlp]

It was basically porting emulators instead of actually producing new stuff that proved Sony PS2Linux wasn't worthwhile to produce, thus all the stuff it happened afterwards with Linux on PS3 (which contrary to PS2Linux lacked hardware acceleration), and adopting FreeBSD.