Comparing a boat to an RV is comparing apples to oranges and they are totally different as far as motion goes.
In my younger days I spent a LOT of time in a small boat and in some pretty rough water so I know what it can be like. I enjoy movement in a boat, whether it's small or large but I hate floor movement in a TT.
In comparison, movement in a TT is much higher velocity and frequency, much smaller amount of actual movement and is of a short duration. It can and does occur in 3 directions (vertical, fore/aft & left/right) and often simultaneously. Sometimes it's just vertical movement from walking inside with dampening oscillations or at it's worst when someone climbs the entry steps and felt as a series of transient pulses.
In addition, not all TTs are the same. Bounce/movement depends on a number of factors such as overall length, weight, frame strength and axle rating (spring strength). Some may be able to tolerate movement better in some TTs but less in others.
As an engineer, I don't buy the notion that movement in a boat can be likened to an RV. If someone doesn't mind all the movement, that's great but the vast majority of RV-ers use stabilizers of some sort. Just take a walk around a CG and see what others do. But then, being an engineer, I have a different take on the performance and expectations of mechanical things than a lot of others. :D