u are hand waving a bunch of dumb shit like "app opens a port and then the app is gone
There's the exact problem though. Why do you THINK the app is gone?
If the app has permission to open a port that means it had permission to have a long-running service sitting on that port.
Why else would it open the port if it were not going to do just that?
Most non-technical users rarely if ever delete apps...
I mean, I agree that android phones are utter shit
They aren't at all, they work really well.. it's just that they ALSO bring the same security risk as any PC to a group of users who by and large have no technical ability to understand, or deal with the risk they are taking on. Sp it propagates the decades of horrible security flaws the PC world has enjoyed, like bank account being compromised, or identities stolen.
It bullshit to claim that is OK, that it's not really a problem when it is a massive problem that affects the people who can least afford to deal with it.