In general people over-generalize. It gets very old. Calling LN a failure is an example. It has issues. It may not be the solution to scaling bitcoin to mass adoption. Only time will tell but it is a step on the road and is working for many bitcoiners today.

Here's some advice. If you are gonna call something a failure you first need to consider what were its stated goals. Has it failed to meet them? If so, is there anything to be learned from it? If both are no then yeah, its a failure. That however is rare.