Foveated rendering will depend on game engine implementing it, various other headsets have eye tracking or add-ons, but this might be the cheapest to do so (at least until Facebook's Cambria or whatever is released, that should cost more than Quest but probably still less than a console + VR).
People are surprised the latest to launch, which still hasn't, may implement more features? Index is almost 3 years old at this point, do people expect every company to release a new VR kit every year making the last obsolete because some other company might release one later with more stuff?
If a year or two after PSVR2 more PC/stand alone kits release with this or that piece of tech over it do you expect Sony to also release an updated PSVR2 rendering the current obsolete on the spot or are you going to then use this same point or say it's good enough/should last this generation
Valve being unable to reduce the cost and the pricing is a separate point and also has to do with their decision to keep using their best-in-class lighthouse tracking making every component more expensive. If they do an inside out tracking kit it'll perform worse, on par with the rest & cost less.