The Apple Maps app on iPhone, for example? If you make it fair and count the code that goes into the frameworks specifically for it, it's still tens of megabytes at the most. There is a huge part of it running server-side to support it, of course, but it is difficult to say that it is not a complicated app. Or consider the Mail app? It needs to deal with IMAP, and has custom flows for a number of named mail services (Gmail, Yahoo, etc.), and then it has to have special code to handle all the edge cases of "what happens if the user deletes a message here but it didn't sync, or Google sends us 503s sometimes if we do this, or…" You can make arguments that maybe it is slightly less or more complex than Uber, but it is just a couple dozen megabytes and not hundreds.

10s of megabytes? Where did you pull that number from? Since it is a system app, its true install size is hidden away from users. The comparable google maps app is 190 MB.

I counted up the system frameworks it relies on that can be reasonably considered to exist for the purposes of serving the app.