Sure enough. The comment that sparked your remark didn't ask for anything all that unreasonable though. Using a sensor around 30 MP in the 1DX III would seem very realistic to me.Whether cameras or data centers, processing capacity and storage are ALWAYS an ongoing issue.
The EOS M6 II handles 14 FPS at 32.5 MP with full autofocus, despite being limited by a tiny form factor (bad for heat dissipation), a low capacity battery and a price tag that's only a fraction of what the 1DX III is expected to cost.
We're only talking about a 32% increase in required throughput, going from 32.5 MP 14 FPS to 30 MP 20 FPS. If Canon would want to do it, I sure hope they could.
If the X III will have a 20 or 24 MP sensor, I'm inclined to believe it's because the market required it, not because the technology didn't allow it. I simply find it hard to believe that Canon went all out with what they can do in terms of throughput with the M6 II and won't go above that, even with their newer flagship bodies.