An 8 core 2nd generation Zen chip appears to retail for $290. The PS5 reportedly has a custom GPU design, but for comparison a Radeon 5000 series card with equivalent CU count (36) currently retails for $270 minimum. Also, that GPU only has 6GB GDDR6 (other variants have 8GB) but the PS5 is supposed to have 16GB. And we still haven't gotten to the SSD, PSU, or enclosure.
Of course it's not supposed to hit the market until the end of the year - perhaps prices will have fallen somewhat by then? (Also I don't expect Sony to be making any money off the hardware at those prices, so I agree that they're unlikely to sell them to anyone who won't buy games for them.)
I haven't looked at what a GPU equivalent would be, but by the time PS5 hits the market, I doubt going to be anywhere near 270$.
As long as there aren't any supply chain disruptions (as there are now).
It appears that the real killer is the hardware-accelerated decompression block pulling the data straight from SSD into CPU/GPU memory in the exact right location/format without any overhead, which isn't available on commodity PC hardware at the moment.
I found some historical price data and I'm surprised - the 2700 really was $150 back in January! Vendors are price gouging the old ones now, and the 3700X is currently $295 on Newegg.
As far as the GPU goes, an 8GB from the 500 series (only 32 CU, released 2017) is still at least $140 today. And noting the memory again, that's 8GB GDDR5 versus (reportedly) 16GB GDDR6 so I'm skeptical the price will fall all that much relative to the 6GB card I mentioned.
I think console hardware cost is generally budgeted at a slight loss (or close to break-even) at the beginning of a console generation, and then drops over the ~7 year lifespan.