Its getting there, 5600X is now £240, 5800X is £350.
Mores Law is dead thinks Intel are not going to increase pricing, so a 12600K would cost $260, i think he's delusional, Intel's 10nm is still not yielding well and it looks like the die is larger.
Motherboards are going to cost even more than the already expensive Z590.
The performance difference between Rocketlake and Alderlake is mostly due to DDR5 which i think will cost about 50% more than DDR4.
I think Intel will sell more Alderlake than they sold Cometlake and Rocketlake but they will sell them at the high end.
People who buy i5 or Ryzen 5 are not looking for the best performance, they are looking for the best price to performance ratio and they are looking at the platform as a whole, a DDR5 Alderlake i5 will cost a LOT more than a Ryzen 5, probably more even than a Ryzen 7.
As for those willing to pay pretty much whatever it takes to get the fastest CPU, that is where AMD will be putting Zen 3D 5900XT and 5950XT, it will depend which of them is faster, the 12900K or the 5950XT.