You connect to Loon balloons with your regular cellphone whereas StarLink requires a "pizza-box-sized" antenna. They solve slightly different problems.
https://www.aboutamazon.com/news/innovation-at-amazon/amazon...
More people are willing to buy a phone and a phone plan (Facebook was even willing to subsidize the plan in India with Internet.org) than buying a phone, a phone plan, an antenna and a StarLink plan. That's even more true for people who aren't internet users yet.
I don’t know what kind of barbaric society you hail from, but here in civilization 12” is a small pizza. ;-)
That's quite a bit bigger than even a large pizza.
I measured out 59cm on a measuring tape and compared it to my refrigerator, and that's much larger than any pizza I have ever seen.