Magnetizing power (and other constant-term losses) are a very small portion of the rated turbine power in a doubly-fed induction generator (DFIG).
Edit (one more thing): At this scale, permanent magnet (PM) machines aren't much more efficient than DFIG machines. It turns out that eddy current losses in the stator back iron remain as a significant term in both machines. But for a DFIG machine, the eddy current losses at light load are reduced by quite a bit relative to the losses produced by a PM machine. Since real-world wind turbines end up operating at partial load for much of their life, the effects basically wash out, or are even a net negative for the PM machine.
Edit (one more thing): At this scale, permanent magnet (PM) machines aren't much more efficient than DFIG machines. It turns out that eddy current losses in the stator back iron remain as a significant term in both machines. But for a DFIG machine, the eddy current losses at light load are reduced by quite a bit relative to the losses produced by a PM machine. Since real-world wind turbines end up operating at partial load for much of their life, the effects basically wash out, or are even a net negative for the PM machine.