A quote from "Diamonds are a Girl's Best Friend",i.e. a little humor,
as opposed to a strawman.

Offhand I can't think of an obso semi because I am primarily a
homebrewer and usually if a solid state project doesn't have readily
available parts I don't start in the first place. They are definitely
out there though. Usually it's an IC for which there is a similar part,
but it doesn't match the PCB layout at all. You wind up building a
kluge board. I have worked on solid state home organs where the
generator IC is NLA, but a third party has a prefab module (potted of
course) that replaces it. The organ in question also had a dead solid
state power amp but we took it and the speaker out and put in a line
level out. The owner then just used a commodity keyboard/bass combo
amp, with complete satisfaction.
What kind of tube was it your three watt push pull amp used?