they probably get saved and converted back to stock
Not sure about that.
I expect they were likely discarded or sold to people that couldn't make one themselves and when it developed some problem, simply abandoned. Mine has a similar story behind it. Back in the day, it became uncompetitive with the canyon carvers, parked and replaced with a newer, faster bike.
I'm not converting mine back to stock. It's got aluminum wheels, fork brace, lower bars than stock, pod filters (blech), and a four into one with a stubby muffler that was described by the PO as "quite loud".
It will still be custom and not stock when I'm done with it. I'm not going to bother with engine internals so long as they're still good. But, this was a bona fide cafe racer in the early eighties, carving up Highway 9 locally.
I'm tempted to "restore" it closer to what it was (a street racer) and running well, rather than make it a more "modern" cafe style (track bike emulator) with the bars down by the tires.
If my back can't take it, then I'll sell it, I suppose.
Cheers,