It's already there for many unsuspecting users. You have to root your iPhone to begin to investigate what might be spying, let alone stopping it, and Apple is doing their best to make the phone unrootable. Soon it won't be (practically) possible.

And not just Apple, they're just one of the first with effective lock-in, and market-share.

Soon having programming/debugging tools could be ample evidence of intent to criminally (the only way) access a computing device.