'air' has it's own turbulence.
and an air bearing softens bass to some degree when used in an arm....when compared to the best solid bearing tone arms.
up to a point the air bearing arm is better; but then the best other designs keep getting better. there are aspects of the air bearing arms which are wonderful....and if those things are most important then that is a different story.
There are always compromises - you are right, air is a fluid and is surely compressible. Designers choose the adequate surface area and proper pressure and flow to optimize the bearing for their sonic priorities, but can not operate miracles.