There would be an upper limit, but where is it? Maybe something less exotic than liquid nitrogen (like water cooling), though who knows without trying it. Maybe even a solid air cooler could do it, or at least get within a few percent of it.

The concern is that a lot of the cooling solutions that are common in the market could be substantially worse than that, or even motherboards that can't supply that much power and are correspondingly configured not to.

It implies that a small form factor machine may be a lot slower even if it has the same processor in it.