A weak vacuum was first produced by Torricelli in the early 17th century using a long mercury-filled tube, but the manufacture of an effective vacuum tube takes you right back to the same high-performance pneumatic engineering I mentioned for compressed-air storage — the first effective model produced by JJ Thomson in the mid-19th century, thereby discovering the electron, which was a necessary step for this to be even imagined.
But, to be fair, it's simpler than a semiconductor.
You can create an effective vacuum in a glass tube by filling it with mercury, inverting it, then heating the tube and pinching it off. This is all low tech.
BTW, Edison discovered vacuum tubes by playing around adding extra electrodes in his light bulbs. But he didn't realize what he'd discovered, and it went nowhere with him.
But, to be fair, it's simpler than a semiconductor.