Engineering question: Tube Camera Survivability

[sdsw4]

So in coupling with my other thread about the M3a, I bring this question for engineers.

In my collection, I have the Sony M3a (being worked on) as well as a similarily aged and even more beat-up HVC-2200.
However, right now, somehow the consumer 2200 is the only tube camera I have that is actually operational. And I bought it partially broken out of a pawn shop.
Debut 8.jpg

Seems like the professional camera should have 100% outlived the consumer camera, but instead the professional camera needs the overhaul while the consumer camera runs fine.
So my question for preserving this hardware is, what exactly determines how a vintage electronic television camera survives as operational for 30+ years? Such as what forms of maintenance, design, use and storage allow some cameras to outlive others?