I think Samsung approach to VR is the best so far. Millions don't mind shelling out money for a premium smartphone, an advantage consoles don't have, and for a little more, you are ready to experience VR with Samsung high end phones.
I think the only way this form-factor will get mainstream is by being a cheap add-on. *claps for Samsung*
Going mainstream isn't the only measure of success though, PSVR's main mission, just like many other VR headsets, is to get the ball rolling, get developers to create unique VR experiences, and refine the technology and make it cheaper as we move forward.