What I've been saying is methodology is mostly irrelevant, not that waterfall is specifically better than agile. Talent wins over the process but I can see how this idea is controversial.

I’d need to see some real examples of high talent, no process, teams compared to low talent, high process, teams, then some mixture of the groups to make a fair statement. Even then, how do you measure talent?

Yep, even if I made it my life's mission to run a formal study on programmer productivity (which I clearly won't) that wouldn't save the argument from nitpicking.