"but maybe the underlying point was that it isn't possible to statically know how much stack size would be required." Given the time frame you're talking about

"but maybe the underlying point was that it isn't possible to statically know how much stack size would be required." Given the time frame you're talking about, remember to be thinking in terms of kilobytes, not gigabytes. And potentially low-single-digit numbers of kilobytes. It could be in the range of hundreds of bytes dedicated to stacks at the time. Even if you could compute your maximum size it's easy to imagine people balking a the results of such a computation and think it's not worth it to even consider the possibility because you'd blow your stack so quickly it's not like there'd be any benefit to it.