It's doubtfull you ever will. It's way too high tech to be built at home unless someone approaches the HW like a PC which would end up being as cumbersome as a PC. A person with little to no electrical training can build a tube amp, given proper set by step instructions and a few simple hand tools. I think the death-knell for tubes will be environmental or labor related most likely. There's some nasty bi-products that contaminated the site at the old RCA plant in the USA and clean up was not cheap. Evironmentalists in the 1st World aren't liekly to ever let a plant like that be built again. Tube manufacture is still very hands-on and automation is limited. Maybe someday robotics could take it over but that would only be attempted I think if the market share was high enough and to be honest it probably won't get any higher than it is now. It may not reduce as quickly as some are predicting either though. SO if you look at where tubes are currently manufactured (only two manufacturing sites really with a lot of rebranding and some build variations for spec) and you'll see they are being built in places where environmental laws are lax to non-existent and labor is cheap. WHen this changes folks will either have to poney up for the cost increases or watch them get discontinued.