If you were actually open to the idea of level 20 'mundanes' doing awesome things, you would drop point 2.
Being level 20 is an extreme level of 'he just trained really hard'. Only one in millions (if not billions) reach that level. Of course it leads to doing fantastical things that people thought to be strictly impossible; after all, it is very possible that nobody else ever achieved it before, and just as possible that nobody else ever will.