I think, the "useful" part is more covered by libraries than everything else, and the stability and flexibility of the core language certainly helps with that. Common Lisp is just not very popular (as every lisp) and does not have a very big ecosystem, that's it.

Another point for stability is about how much a runtime can achieve if it is constantly improved over decades. Look where SBCL, a low-headcount project, is these days.

We should be very vigilant and ask for every "innovation" whether it is truly one. I think it is fair to assume for every person working in this industry for decades that the opinion would be that most innovations are just fads, hype and resume-driven development - the rest could be as well implemented as a library on top of something existing. The most progress we've had was in tooling (rust, go) which does not require language changes per se.

I think, the frustrating part about modern stacks is not the overwhelming amount of novelty, it is just that it feels like useless churn and the solutions are still as mediocre or even worse that what we've had before.