"Server systems" but not server systems that Microsoft targeted. NT4 Enterprise Server (1996) only supported up to 8 sockets (some companies wrote their own HAL to exceed that limit). And 8 sockets was 8 threads with no NUMA back then, not something that would have been an issue for the purposes of this discussion.
That was what stuck, but supporting the big servers was also part of their multifaceted strategy. That's why the alpha, itanium, powerpc, and mips ports existed.
