It seems like most of these things should be downloaded on demand or at least after the initial install and in background.

Same with dev experience. You shouldn't have to compile things you are not using to dev.

This would give pretty much infinite scaling.

I do think Uber requires tons of engineers, but I disagree that all of this has to be downloaded immediately or bundle size has to be this big.

All of what can be logic wise should be server side. For instance Airport logic seems like one.