I'm not sure I agree with the strategy, though. It seems really challenging and dangerous to put such huge satellites into LEO. They'll require constant maneuvering. NASA seems to think it'll require 4 maneuvers per day, https://space.stackexchange.com/questions/49981/why-do-ast-s...
I will put my money on cheaper, more disposable satellites because they enable rapid iteration cycles with less risk.
So big in fact that a couple of months ago the US space agency NASA, having looked at SpaceMobile's plans, complained the "extremely large satellites when in orbit will engender an unacceptably high risk of a catastrophic debris-producing collision."
I don't know enough about this area to really comment, and they did reach an agreement with NASA the next year, but it still seems like there's something to be said about the size of the object being maneuvered.
You're right though that SpaceX has to deal with a lot more. I guess I just figured that in failure scenarios they'd deorbit a satellite, and shrug it off, where as AST SpaceMobile can't tolerate losses.
AST also seems to be favoring a different strategy, having a smaller number of satellites each capable of serving a larger number of users vs Starlink's thousands of satellites serving a couple of users each. IMHO AST's approach sounds more sensible and manageable (albeit both approaches manage to equally annoy astronomers). Whether they will be able to really serve a large enough number of users or not also depends on the chip science (rather than the rocket one).