I wouldn't say vacuum tubes are worthless. A pair of WE 300B tubes go for way over $1000. But they are temporarily not being built. I have a client who owns the manufacturing rights, but the plant has been shut down for awhile. There is an order backlog of several thousand pieces, mostly to go overseas. The space in a new building has been allocated and cleared, but room construction still has not started nor any rebuilding of the machinery.