That and the fact that we have plenty of gravity on Earth. We go to space to study things that we can't study on Earth.
The force of gravity in low earth orbit is about 91.7% of the force at sea level.
The apparent force, which is what we experiment with, is much less.
But it's far easier to maintain prolonged free fall in orbit.
There is also about no experience with it, so a lot of work, money and mistakes are needed. Structural integrity is a big challenge. As I see it, it's not that people there do not think about it, it's just not feasible right now.