Completely agree. The core tenet has been lost. Monero is closer to digital private money than anything else right now. And in my view, worth the cost of POW.
There's some independent research there but AFAIK Bitcoin people did not stop working on confidential transactions or fungiblity.
Just explaining that the core tenet was not lost, but that it was still not researched. Bitcoin jump started a research movement that reaped all kinds of cryptocurrency variants as time went on.
https://electroneropulse.org/public/doc/Bulletproof%20RingCT...
Here's a paper whose coauthors belong to the Bitcoin team discussing efficient confidential transactions that were eventually implemented in Monero (not by the Bitcoin team).
The knowledge held by the Bitcoin team wouldn't disappear if Bitcoin was shut down. They could still contribute to other crypto projects.
There's so much stuff that still had to be researched after Bitcoin came out.
One big example that comes to mind is SegWit.
The cryptography was still not there and I do not feel that something can be lost if it's not there.