Not only is he dead serious, you're overlooking the fact that a lot of people are doing literally that. His figure comes from reasonable projections based on averages and such. The fact is the Bitcoin network does pour out 20ish TH/second, and has roughly for months and months and months. This is literally millions of dollars in op costs, and a lot more than that in fixed costs.

To ease the point into a "low information voter" sort of mental context, think of it in terms of television: you buying ten or twenty television sets does not make you "one of the top 20%" people in television. Even if they are all top notch plasma screens or something.