Most likely PC VR buyers already have at least average computer. The only thing they will lack is GPU and maybe RAM. GPU upgrade would cost them 200$, so total would be 500+200=700$ and only if they don't already have any sufficient GPU for 2D gaming.

Assuming their computer is upgradable and not a all-in-one.

These days that's not so expensive. $600 will get you there.

So $3500.

You can build a computer that could run most of the games for like $600.

The problem with VR is dropped frames has a much stronger effect than it does when the same thing viewed on a monitor, too many and it can be instantly nauseating. You want consistent, very high framerates. You're also driving two fairly high resolution screens.

That requires a GPU costing at least $600 to do right. Then you need a computer to drive it.