Certainly true for some people, but not for many people. For example, on the SpaceX Inspiration 4 mission one of the four people had serious motion sickness issues, but the other three were okay.
Should be relatively easy for space tourism companies to develop techniques screen out those who would likely not be able to tolerate zero-G.
Space Adaptation Syndrome affects roughly half of those who spend time in orbit or beyond, and the symptoms range from debilitating to merely mild and often resolve in a few days. If they didn’t, getting work done on the ISS would be impossible and we know those astronauts have a very full and demanding schedule during their time on station.
As for the Zephalto balloon idea, personally I am not interested. If I am going to spend all that money to go that high, I want to experience weightlessness as part of the trip. But I’m sure there is a market for that kind of balloon trip.
This will be my first step before hopefully — some day — going to LEO.
https://www.gozerog.com/