IIRC some of those researches you're taking estimates from not only used cherry picked figures for AI image generators, but also massively underestimated man-hour costs of human artists by using commission prices and market labor rates without requisite corroboration works before choosing those values.

Their napkin math went like, human artists take $50 or so per art, which is let's say $200/hr skill, which means each art cannot take longer than 10 minutes, therefore the values used for AI must add up to less than 10 workstation minutes, or something like that.

And that math is equally broken for both sides: SDXL users easily spend hours rolling dice a hundred times without usable images, and likewise, artists just easily spend a day or two for an interesting request that may or may not come with free chocolates.

So those estimates are not only biased, but basically entirely useless.