1: VR brings in a whole new medium of 'gaming', also games as we know them today are no longer called games but instead known as experiences.
2: Yes, this is actually already here (look up Gear VR, Oculus Rift, PSVR, HTC Vive), to answer your question about the future then yes it will become mainstream and eventually merge with what we currently know as AR (Augmented Reality).
3: No we won't get 'stuck' in VR, it doesn't work this way and a VR machine in the way you are describing it never comes to exist, instead VR headsets become standalone and will begin to look like those old style steampunk goggles, shortly after this AR goggles are merged with VR ones. They are made to be worn in public and can be easily worn and taken off at any point in the experience.
4: We don't get quantum computers for a very long time however computers change when stand-alone VR headsets and 5G becomes standard, at this point the internet is now accessible almost the entire globe over at speeds that'd make any geek drool over today, fixed line services die out surprisingly quickly as 5G is both cheaper and far more reliable. Computers themselves shrink and become more portable however the fabled desktop doesn't die, screens are large and look similar to todays without bezels and are fully 3D without glasses. We're in for a great time if you're a geek.
5: Not possible and won't be possible for a long time, the worst you could do is make someone really dizzy as some of the more advanced headsets affect your inner ear to alieviate simulation sickness so you could make someone feel like they are upside down but only until the headset is removed.
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