It's mind blowing. It's so simple, elegant and... effective! Grep+glob and a lot of iterations is all we need.
No amount of find+grep+LLM is even remotely there yet.
What do you mean Turing complete? Obviously all 3 programs are running on a Turing complete machine. Xargs is a runner for other commands, obviously those commands can be Turing complete.
I haven't heard of anybody working on a _proof_ for the Turing completeness of xargs, and I think the only conference willing to publish it would be Sigbovik.