Yeah, although a bunch of work on Monero is still a result of work from people that worked on Bitcoin.

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).

"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.

Yes, but saying that the core tenet was lost is a bit dramatic. The guys working on it were still interested in other aspects of cryptocurrencies that bitcoin does not implement. Bulletproofs coming out in 2017 meant that Monero had inefficient fungibility and confidential transactions before, bloating the blockchain before they implemented bulletproofs.

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.