Lore wise weirdly XIV implies pretty heavily that flight is not a mechanical function but a magical one for many creatures, and that doing so safely requires understanding an area to a certain degree.

So it isn't actually that wild for the PC to just learn to fly in the same way we sorta just got the ability to breath under water.

The bigger issue is genre, which in a lot of ways trumps lore and theme. It doesn't really matter if something is hypothetically possible if it doesn't fit the genre, and in fantasy its sorta weird for your characters to fly around like superheroes unaided, compared to riding a mount or a broom or whatever.

Its the same reason that Star Wars didn't devolve into different sides using Von Neuman Probes to murder each other and convert entire star systems into mega-structure factories: sure the fact automated droid production combined with the fact that droids themselves could be technicians and producers and spaceships makes this a logical inevitability, but then you are less talking Lucas and more talking speculative hard scifi and moved into a different genre entirely.