That being said, any other services could be shut down via an aqui-hire, or other reasons. Maybe this is the prevailing problem of small time developers like myself, and there's no other way around it apart from getting your idea bootstrapped with these services, and hopefully by the time any of those services gets shut down (if ever), you'll have a migration / backup plan of some sort.
This is surprising to me, but I wonder if Google Maps could close down....
No. Google has bought what must be dozens of companies at this point just to support and improve Maps (Waze being the latest), it's reportedly profitable & popular, with the continued rise of mobile I'd expect it to become more important, and my little survival analysis (http://www.gwern.net/Google%20shutdowns) gives it 87% odds of surviving to May 2018 (which IMO is too low).
I saw a bunch of public linkedIn profiles with NSA analysts and people in the private sector with google maps listed as experience for whatever reason
The best way to tell what direction you were facing when you came above ground from being on the subway was to look at the direction of traffic aligning with the arrows on Google Maps... but they decided that was no longer an important map feature and got rid of it.
I would frequently be zoomed into a specific location, and relatively soon after need to switch contexts on the OS (to check an email, answer a text message, etc.). When I returned to the app it used to be that it would retain the zoom level, but after updates it seems that Google thinks it's useful/funny/cute to zoom back out to the full zoom of the overall trip. For the life of me, I can't imagine a context in which this is useful.
They've got a monopoly on mapping data, and insist on taking a great app and making it worse. I can't understand why.
If your device has no inbuilt compass (think iPhone 3G, from memory), there's nothing Google Maps can do about it.