> Computers didn’t exceed 64 logical processors per system until around 2014.
Server systems were available with that since at least the late 90s. Server systems with >10 CPUs were already available in the mid-90s. By the early-to-mid 90s it was pretty obvious that was only going to increase and that the 64-CPU limit was going to be a problem down the line.
That said, development of NT started in 1988, and it may have been less obvious then.
"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.
Server systems were available with that since at least the late 90s. Server systems with >10 CPUs were already available in the mid-90s. By the early-to-mid 90s it was pretty obvious that was only going to increase and that the 64-CPU limit was going to be a problem down the line.
That said, development of NT started in 1988, and it may have been less obvious then.