That wouldn't have fared much better.
Heat-wise, yes it wouldn't have helped but they could have gotten better than RKL IPC. Some dumb group of Intel engineers gets very excited at the prospect of high bandwidth RAM. That's why they wasted their time optimizing ADL for DDR5 and mispredicted DDR5's rate of adoption. They could have simply worked more on getting their IMC to play better with DDR4-3800 or DDR4-4000. Their fetish for DDR5 led to getting forced to release RKL to buy some more time.
I also blame idiot Intel marketing folks. Here's the sort of discussion they had:
Q: When is AMD going to release their DDR5 parts?
A: Not on time.
Marketing: Great! We can hype up the massive benefits of DDR5! We'll be first to market!
Engineers: Umm...there's the issue of higher latency...
Marketing: Who cares??? DDR5-4800 looks so much better than DDR4-3200. It's a no contest on paper!
And Marketing won.
I have enough rage right now to incinerate them, just by looking at them
