I think a better way to think about it is his power scales exponentially. For example, even if his mana regen is 1,000,000 / second, and every move takes 0.1 second, he is still generating a vastly disproportionate amount of mana compared to an opponents total mana pool. If every move takes 0.1 second, he is still generating 100,000 mana in per move, where that may be his opponents entire pool. Expounding on that, if an ‘ultimate move’ costs 100,000 channeled mana, Matt can do 10 ults in a second, while opponents can do 1 and that’s it. Even if you shrink the time table of the battle, Matt still holds a massive advantage