You have an interesting hypothesis for sure, one which could be tested in the near future by commercial space flight i.e. Virgin Galactic and SpaceX. I'm absolutely clueless if there could be an effect or not, considering my lack of personal experience with high altitudes. However, I'd like to address somethings about virtual realities, their nature, and the one we are in currently:
slip the surly bonds of Earth
Earth and Space are both part of the same PMR. Our consciousness is constrained to this entire PMR which includes everything outside of Earth also. Slipping the surly bonds of Earth is a matter of physics and spaceflight, slipping the surly bonds of this PMR is a matter of focused intent and QoC (or binaural beats, or hallucinogenic drugs).
As far as a specific altitude threshold, that too may vary according to the QoC, the FOCUS of the consciousness and the strength of the gravitational field
Gravity is "coded" into the ruleset (it evolved to be more specific, but let's treat it like a coded/programmed property). Like any video game there is an aspect of gravity coded into it. A person of this mass may only jump this high. In our video games, there isn't anything special about gravity, it's an easily modeled effect. Also, it doesn't matter what level our players are in these video games, they are all effected by the same gravity in the game. There isn't anything special about going very high in these video games either, although if it's not coded very well perhaps there are some glitches when you reach the outer bounds of the programmed environment. That being said, The near space right next to Earth is no where near the outer bounds of the PMR environment.
I don't know where this is going, but it may be that a gravitational field plays a big part in keeping a consciousness focused on a PMR environment such as Earth. Which, if one extends the concept further, could affect space exploration.
As for this, I'm highly skeptical. The PMR environment is everything in this universe, not just Earth. Also if this indeed was true, that gravity focused you in a PMR environment, I don't think the LCS would have any problem changing / reversing this effect if we as humans become a space-traveling civilization. Just "change the code" in one iteration of a Delta-T and viola! no more effect. Simulation continuity and consistency is of the upmost importance.
For now though, I'll keep it in the "possible truth category." We need more data in order to validate or falsify!