Some of this seems far fetched.

Most power grid noise is fairly well handled by the PSU and motherboard, it's half the reason for the mega capacitors.

As for radio wave noise, that just sounds like BS. It would only really affect higher frequency chips, and those almost always have a metal heat spreader. Further, many cases are metal as well. This makes your computers Faraday cages. IDK, maybe more an issue for mobile computing. However, seems like the solution is simple, just add more metal.

Cross talk and power fluctuation from processing is a more tricky problem to solve. You could possibly fix power fluctuations with more on chip capacitors for sensitive circuits. Cross talk is harder, afaik, the only solution is more spacing.