I had the same intuitions when I began exploring this. Fortunately, the concept of ‘continuity’ knocked my mind and I found something interesting. There is, of course, a maximum theoretical limit for the maximum efficiency of a wind turbine. Check out Betz’s Law.
No turbine can capture more than 16/27 (59.3%) of the kinetic energy in the wind.
Besides all this, there is a bigger problem when you come to larger turbines. If you add more blades, the component cost per wind turbine increases way high compared to the energy you obtain from the configurations. Also, the weight increases with each blade along with the torque. Higher torque will need stronger structural parts like more efficient gear boxes, break shoes and yawing gears. It’s quite complex though.
