There's also like one company still manufacturing CRTs, and their market is exclusively military and heavy-industrial, replacements for old fighter-jet HUDs and the like:

https://www.thomaselectronics.com/avionics/head-up-display/

I'm sure there's at least one wealthy Smash Bros. enthusiast willing to pay their asking price and hook up one of their HUDs to a Gamecube to play Melee though.

I was under the impression that you could purchase cheap newly manufactured CRTs on alibaba. I only know this because someone published an unrelated project that repurposed the electron gun and associated internals.