I think it's because architecture-wise, these are more in line with the 8000 series. The 7500F is a full featured Ryzen 7000, but with broken graphics. These are basically 8000 series APUs, so they have the lower PCIe version, lower cache and fewer PCIe lanes, and broken graphics.

I suspect the price will come down soon because no one should be buying these at this price. The 8400F is only $10 less than a full 8500G.
Edit: I just saw that the 8400F is a six-core, so maybe that helps justify the price.