[blazespin]

Another factor is simulator sickness. Even if you could get the perfect 3D environment going (say via the Oculus Rift), your inner ear will start to complain that what it is seeing is not matching what it's feeling and your stomach will thinks its been poisoned and induce vomiting.

The only way '3D' will ever work is if the movie is jacked straight into your brain, ala 'Strange Days'.

[dwild]

The same happen on a boat and as far as I know, there's millions of people on boats everyday.

[MBCook]

There are millions of people who avoid boats for that exact reason.

[TheZenPsycho]

You can always strap on one of these vestibular stimulating systems: https://www.youtube.com/watch?v=Kf0E9llkZIU