Actually, it makes sense, if you consider they can seemingly command their individual feathers to a degree (the outermost feather in the tip of the wing in particular), like when RD and Lightning Dust when they introduced each other, and when RD clipped her right wing cuz of LD's recklessness, and Soarin could still straighten his wing (which went back to retracted state like a rubber band) after he clipped it (but couldn't fly, RD barely could with a clipped wing), and some Pegasi (the one I'm thinking was a standard mare) are seen lifting 2x100kg+ weights on the ground with both wings just like we humans do with hands on a bench. 100kg+ ! Man, even an average human male has to work for real to get those up ! That makes me think the average Pegasus wing is strength-wise strong, but flying ain't nearly as easy; a Reddit comment thinks the standard G4 pony would weigh 56.7-159kg depending on whether one is Earth, unicorn or Pegasus, with Earths being workhorses would weigh the most, unicorns the middle and Pegasi the least since they have to be able to fly. I've never seen why real-life horses and ponies weigh a few hundred kilos, but I think a standard G4 mare would be less than an average human man and a stallion more than average human man.