> but a significant chunk of work and effort and effort recently seems to be pointed at the direction of bending and twisting the Bitcoin protocol so that it works better with one specific implementation of an offchain system

Work on what by whom and to the exclusion of what, exactly?  Please provide hyperlinks.

It's kind of exhausting to deal with what feels like pithy narratives being used as a substitute for actual reality. We can avoid anyone feeling that way by being painstakingly concrete instead of vague.

You provided two links:

BIP 118, which is over two years old (Feb 2017), has no activity in Bitcoin Core right now that I'm aware of, and was written by a lightning implementer. Lightning implementer interested in things that are useful for lightning isn't a newsflash.

And PR12254 (Apr 2018) provided for BIP158 filters doesn't do anything for lightning as is, and was developed by someone who isn't a project regular.  Much of the interest in that is making wallet rescan fast [search this for BIP-158]., which that PR implements most of the necessary components for... and a network facing version is essentially just a replacement for BIP37 which is slightly less of a total privacy disaster (and DOS vulnerability disaster). There isn't anything lightning specific about that...

I don't think these support your case, if anything they contradict it-- or at least the fact that these were your only examples does since they don't show a high level of attention or interest.

Lightning is an application of Bitcoin smart contracts to make Bitcoin payments more efficient, the fact that it could be adapted to another system is simply a product of other systems copying Bitcoin functionality... the same could be said for any technical functionality.  Any application seeing actual use is obviously going to get some engineering attention, since a real application with articulable tradeoffs generally trumps conjecture.