So can we skip the right-wing talking points, please? Tube manufacturing was certainly no more toxic than semiconductor fabs are (one of the most toxic industries around), and they aren't going away because of EPA regs.
US tube manufacturing died because the market for tubes went away VERY quickly once solid state devices took over in the late '60s/early '70s.
One example would be RCA, who introduced their first 100% solid state (except for the CRT) color TV sets in 1969, and closed their receiving tube plants (the largest in the US) by 1976.
With 15-20 tubes in a typical color TV set, there was a HUGE replacement market for receiving tubes and many US manufacturers each with several plants to meet the demand. Typically you would need to replace 2-3 tubes a year in a TV you used regularly. Self service tube testers (and replacement tubes) were found in drugstores and hardware stores for folks who wanted to try fixing their own sets.
Once tubes went away in new sets, the market for replacement tubes evaporated within a few years as the older tube sets hit the landfills. The relative handful of tubes still being sold were made in short runs from 1 or 2 US manufacturers who stuck it out until the '80s making a handful of types that still had some demand, but these quietly died by the early '90s, when the US military stopped supporting most of their tube-based gear and flooded the surplus market with warehouses full of unused tubes.
Tubes are still made in the US by a handful of manufacturers, but they are specialized devices used in high powered transmitters, radar, particle accelerators, and such. The ordinary receiving type tubes used in audio gear are largely made in the former Soviet bloc, which kept the remnants of their tube industry alive longer than the West did, preserving much of the manufacturing and raw materials infrastructure needed to serve the modern (much smaller) market for receiving tubes.