Definitely. Microsoft doesn't see commercial value in supporting, eg, a SPARC version, especially when it won't run existing x86 apps. It'd be a huge lost cost

Definitely. Microsoft doesn't see commercial value in supporting, eg, a SPARC version, especially when it won't run existing x86 apps. It'd be a huge lost cost in development just to make one. ReactOS isn't driven by the same market forces. Anybody with enough determination can port it to SPARC and fly away :) Windows NT 4 supported x86, MIPS, PowerPC, and Alpha. All but one were dropped with Windows 2000... and it wasn't until XP that non-x86 returned (initially IA-64, and x86_64 in three more years after initial release).