I mean, that would be a problem in a world where the phone is physically stationary in a far corner of a house hooked to the wall with a wire. And where I would need to schedule time to sit near the phone so that I don't miss the expected call.
However today, I can text ahead of time to see if it's a good time to call. Or check the shared calendar. Or (if we're sharing phone GPS data) I can find out near real time GPS data and approximate speed.
Actually it wouldn't be out of the question for someone to make a product such that I verbally ask my phone to setup a noonish phone call with someone where our individual AI assistants figure out when that needs to happen based on our schedules and locations. And which can dynamically reschedule as real time events happen.