Without Facebook's capital and Zuckerberg's commitment to VR, I doubt the Quest would exist. That project was announced in 2016 and was likely in development for a couple of years before that. Still it took until mid-2019 to be released to the public. IIRC, Carmack said that development on the Go was started after the Quest, yet the Go went to market a year sooner. I can only imagine what kind of hell it was to get a 2016 phone SoC to do VR with 6DOF inside-out tracking.