I dont know, only a few years ago the top gaming CPUs cost $300 and their boards did not cost more than the CPU. Now they run $450.
Inflation happens. The difference is how much GPU's are out pacing inflation.
In 2015, the top selling CPU according to
Newegg Business was the 4790k for $310. $310 in 2015 is worth approximately $385 in 2023.
Today in 2023, one can buy a 5800x3d for ~$320. This may not be the best available gaming CPU but it is VERY close.
Newegg's page shows the best selling CPU right now as the 5700x which is on sale today for ~$200.
The 7800x3d is better than the 5800x3d and costs $449.
$385 to $449 16% higher than average inflation but I don't think that is a fair comparison. You can buy a great gaming CPU like the 5800x3d for cheaper, in terms of inflation, than you could with the 4790k in 2015.
Although it is not an up to date graphic on GPU prices, I think it makes my point with far less typing.