“So, for the PC-98, the answer isn’t really that it died - it sort of faded away and merged into what every other system was becoming.”
NEC’s PC-98 and Fujitsu’s FM Towns ran on the same CPU as the IBM PC, so Microsoft could port Windows to both. Once software stopped caring about the hardware, nobody had a reason to pay for the proprietary box. Sharp’s X68000 used a Motorola 68000 and couldn’t run Windows at all, so it had no exit. Lock-in protects a platform until a hardware abstraction layer makes it a commodity.