I dunno about motherboards and coolers or CPUs getting more expensive.
Remember the days when the top of the line consumer CPUs were $999+ ?
For motherboards, I usually buy used as well. The prices are going up but the components and boards have also gotten
More complicated.
For coolers, if you are taking new prices for Noctua coolers, those have always been way overpriced. Same for their fans.
Used prices are generally significantly cheaper.
Maybe power supplies, but I am a power supply snob for good reason so my power supply purchases has been on the more expensive side for years now. Then again, I very rarely buy new PSUs and have not spent more than $100 on even a 1000w Seasonic.