They’d NEVER have an unlocked cpu in this thing and outside of the two extra cores it’s the same chip. Thermal limits are prohibitive for 33% more cores. There really isn’t any performance difference unless you need all the cores AND can keep them from thermal throttling. It’s why the i9 MacBook Pro ends up being slower on big work flows. It’s all just a sales pitch that processor in this machine wouldn’t make any difference.
The 9700k (8 core 16 thread) is only 5% faster than the 8700k (6 core 12 thread). Want to guess why? Very few apps (literally zero that I’ve ever used) use more than 6 cores.
https://cpu.userbenchmark.com/Compare/Intel-Core-i7-9700K-vs-Intel-Core-i7-8700K/4030vs3937
You’re talking 95w TDP vs 65w TDP vs 28w (Haswell 4578u mobile processor in the 2014).
There’s thermal limits to the same design cube so maybe cut the engineering guys some slack. They just took the Mac mini from an average CPU score of 4758 to over 12,500 (exact number hard to find). and this is just passmark for the CPU. Graphics are much more capable plus hardware encoding and decoding.