It's a real problem. There's a huge overlap between "things that can be abused by ads" and "things that allow boundary-pushing products".
On Desktop, historically we chose the "buyer beware" route which, for all its 10-IE6-toolbars flaws, led to an environment that felt like it was full of possibilities.
On Mobile we are going for a "you get your little sandbox" route, which delegates innovation to the OS vendors only.
These are both outgrowths of where they came from. Desktops came along in the 1970s as (relatively) powerful do-anything machines. Phones came along as simple phone (and later SMS)-only devices that have gradually grown more advanced features.
I understand the frustration, but it is a different threat model. Your phone more-or-less knows your exact location at all times (and has to, by design). In my view this calls for a different set of tradeoffs re: application permissions.
But there has to be a better model than delegating innovation to Apple and Google. It's a huge conflict of interest too, since they are both Ad companies.
We're heading down a path where there are products that only Apple and Google can build, and it's a huge problem for the ecosystem.
And not just location, also who you communicate with (contacts and "phone" permissions), are you currently walking/driving/sitting still, who is around you (wifi and location/bluetooth permissions), it can record audio/video (camera, mic permissions), and it's al based on the user knowing enough to allow or disallow those permissions when needed.
By restricting full-screen, you're punishing the top 85+% of users who are fully capable of understanding what a permission ask for "Is allowed to display full screen while locked" is asking. Generally spekaing, the race to design everything for the bottom 10% of users is resulting is a world of forced conformity, severe artificial limitations, and basically the Simpsons episode where Homer bubble wraps the entire playground, but in a tech sense.
Like ads?
Yeah... Is there ever a thing that wasn't abused by ad companies yet?