It's way more than that. A solid 5/10 HUNL player now can beat every single top NLHU player 3 years ago, probably 2 years ago. Possibly quite a few good 2/4 ones can too. I mean reading back the old hands, my god, those are atrocious, how did we used to make money playing like that? It's insanity.
What you say is more than feasible, though I've known quite a people who made 6 figs, lost most, then made it again, and rinse repeat, so, eh. If you work hard, there's money there still.