So a developer can charge a user a $1 introductory fee, and then $100 for the next fee, and apple gets a commission only on the first $1?
Yes, that's exactly it. Good.
Over-flying the continental US doesn't seem like a big enough niche.
It's a very large niche if you're planning to fly from the East coast to Asia, or from the West coast to Europe.
I don't think that shift will be long-lived because ever more people use a smartphone as the primary device (instead of a laptop), and the median smartphone is something like a Samsung Galaxy A13 even in the rich countries. That kind of smartphone has a terrible JS performance compared to the flagship devices, and it won't be improving much any time soon because most buyers find that sufficient for most daily tasks, and as performance per price improves, when time to replace a device comes they prefer to keep the same performance level for a lower price.
On the developer side, there's already a movement against heavy JS interfaces, and Rails Turbolinks and htmx.org are just the beginning.
I strongly suspect that the lack of popularity is due to the price
And vice-versa, because of the lack of popularity, production is low and prices are high. Also, manufacturers take advantage of that by marketing the high-quality items as "luxury" and charging disproportionate premiums, where the same product made in the EU is often much cheaper (I've noticed this for dishwashers, triple pane windows, etc...).
In case of injury notify your superior immediately. He'll kiss it and make it better.