So, you just want a prebuild? Just as with consoles, you still need to do maintenance. Yes, you can neglect it for a couple of years, but then you start noticing that your thermal interface is not as good anymore or that your heat exchangers are now more dust than metal. And I find full-sized computers easier to maintain, as they are so easy to disassemble, contrary to consoles.

Also, if you want VR and have the money for it, it's probably a good idea to buy a beefier machine. VR is a bit hungry for system resources (depending on the title, of course), standalone headsets don't provide nearly as good of an experiece as a proper PCVR.