Here's the thing though: Will GPUs consume 700w or more power by 2025, if not sooner? Well yeah, of course, MCM designs will allow much more performance density, especially in the industrial side where more exotic cooling methods can be used. This is a good thing, and will increase overall efficiency as much as 64, 96, and soon to be 128 core server processors have allowed 1 server to replace half a dozen or more and power consumption to decrease as a result. I would not be surprised to see high performance server level cards break the kilowatt barrier by 2025 or shortly after, again because MCM allows them to break free of the limitations of monolithic, same as they did with CPUs, and existing industrial chillers can handle them.
In the consumer side? I don't see that happening outside the ultra high end and prosumer level at all, even into the angstrom level.