The crossover might be built in, it's mechanical. No, we wouldn't do that
today, and yeah, it's a bad idea, but check out the Triad System Model One for
instance.
You mean they might have rolled it off intentionally?
Quite possible.
By the way, Manny LaCarubba (Sausalito Audioworks), who's as good a speaker designer as there is, uses subs in his systems. The twist is that he uses multiple ones, not just a single one. So it's not just that era!
At what point does it cease becoming a subwoofer and become a woofer?
100Hz.
http://www.grimanisystems.com/technology/
I heard those in his workshop/office/whatever you call it. After about ten seconds I forgot I was listening to speakers and got drawn deep into the recordings he played.