If there's one archetype that haunts math forums, it has to be the Retired Engineer that took a look at the Collatz conjecture or the Reimann Zeta zeroes and just came up with a theory.
This also happens in physics, but physics crackpots can come from anywhere. Especially now, having been reassured that they've hit the key insight, and you're absolutely right, it's not just a theory of everything — it's a revolutionary new foundation for physics! Would you like me to help you write a convincing paper delving more into these ideas?
My favorite physics crank was the guy who convinced himself that curves don’t exist; they’re merely lots of line segments pasted together. He proceeded to derive a whole lot of remarkable nonsense about astrodynamics, and maybe relativity? It’s been a while.
Maybe ironically, the idea that curves don't exist hasn't gone away, it's still a serious idea: spacetime could be discrete, in which case curves really are a series of discrete line segments. Loop quantum gravity is one such theory, and I would hardly say it's crackpot physics.
This also happens in physics, but physics crackpots can come from anywhere. Especially now, having been reassured that they've hit the key insight, and you're absolutely right, it's not just a theory of everything — it's a revolutionary new foundation for physics! Would you like me to help you write a convincing paper delving more into these ideas?