I don't think the lightning network has failed. I just don't think it was ever meant to be what we're trying to force it to be. It's not a "sovereign payment mechanism". Maybe ecash IS the more sovereign mechanism, but I do think lightning even if only custodially, still has its place.
I watched this video recently and it was hard to disagree with most of his points. He might be a 💩coiner but the critique of lightning seems valid.
https://www.youtube.com/watch?v=5Cq0C0SpbkY
I do not want the future of bitcoin to just be trusting custodians. Hopefully some smart people can come up with solutions. I dont know much about it but ark protocol perhaps?
Discussion
I guess saying it failed depends on what your vision of lightning is.
Lightning has not failed to provide cheap and fast off chain transactions but it will never allow the masses to interact with bitcoin in a self sovereign way.
It might not be a problem that lightning does not solve this but I think it is a problem that there does not seem to be any solution currently for that problem.