All true, but doesn't mean there won't be solutions to these problems eventually. Tethered VR, while a better experience technologically, is impractical for theme park usage -- but so is mobile when you consider the graphical limitations, the need for constant charging/swapping, and of course hygiene issues. Just think about the gallons of sweat that will dumped out by guests coming inside from the gross Florida humidity on these things each day! Yuck.
My point still remaining, Disney should stay away from VR for anything more than a little side show for the time being.
I still think a better usage of VR $$$ is in the home market right now where people who can't make it out to a Disney park can still pay to have a Disney park-like experience. Seems like such an untapped market right now.