pg's notion was psychological, not about languages per se: a programmer sitting in language X can't perceive power above X, only below. It's about a fixed vantage point.
Your "Lisp is just another Blub" would be true if Lispers were stuck looking up from Lisp-as-it-was and failing to see higher. If Lispers were trapped in the Blub position, they couldn't have deliberately imported ideas that sit "above" classic Lisp. But they keep adapting: Clojure added persistent immutable data structures; brought CSP/channels; introduced structural contracts like Spec and Malli. With Coalton and Shen they are explicitly reaching for the static-types level you say they can't see. Racket's whole "language-oriented programming" perhaps a level above any perceived Blub.
Maybe what you see ain't a Lisp ceiling? Could it be that some powers must live in the substrate - and Lisp's distinctive traits are precisely what makes building that new substrate cheap?
I'm unfamiliar with Coalton but the Blub article describes the proverbial smug Lisp weenie. I'd agree with you that #notalllispers.
Most Lispers I met do actively write in multiple languages all the time. They tend to borrow ideas from other PLs instead of loathing everything else that's not their favorite. They prefer Lispy syntax, but won't reject a language to achieve a goal - they'd pick everything - runtime, tooling, etc. and try to find a Lispy syntax that sits atop. While preserving all the remaining semantics. And then they'd argue that syntax does not make a language. Perhaps, Lispers are the largest demographic of polyglot programmers in the global community.