Sure, if you're a hip cool 20-something who does a load of laundry per week air-drying is fine.
Try being a household with a couple kids and a baby under 2 and hanging your laundry everyday. It's a waste of time and frankly sucks. I've done it.
The machine was a pain in the ass. I had to check it so the clothes didn't get too hot or go too long. Once done, you have to fold or hang immediately or you get wrinkles.
Now I just put them up and forget about it until later, often the next day when I want something
Not everybody on the planet (or in the US) has selection pressures that maximize convenience. We’d probably be worse off as a society if that was our only consideration.
Not a big deal at all.