The problem is that instead most people to come to them are either obvious crackpots, who think they have solved cancer (energy...) and contact the person because they are a biologist, physicist ... (on a completely unrelated topic usually). Or they come from a place of arrogance, i.e. "we do ... like this, our method is clearly superior you should adopt it", or even worse here buy our clearly superior method.
Otherwise why not just replace them with a script (or these days, an AI)
And I don’t know many, if any, examples of people received as crackpots that later were considered genius. At worst genius takes a little time to be recognized, which is a situation far more common.
It's like an analog to the fact that almost all people consider themselves funny.
If somebody truly believes they have a useful model then they don't discouraged by academic gatekeeping, they go and build Time Cube.
"Using methodology from a field known for its focus on methodology in another field" was still a novel idea in von Neumann's time. But because von Neumann and others did it, and because millions of people entered science after them, most combinations like that have already been tried. Breakthroughs from combining ideas from unrelated fields require something little less obvious these days.
However, the gatekeeping you mention definitely occurs to mere mortals who might have an interesting bend on existing ideas.