I just don’t understand how we got to a place where the way things worked for decades suddenly doesn’t work anymore. We would leave our homes and not be reachable. Most urgent calls aren’t actually “emergencies.”
Sure, but whether or not that suffices for someone is pretty circumstantial.
Like I said, I don't disagree with your general sentiment, just the absolute. And hey, change happens, c'est la vie.
You're making up a past that didn't exist. During the entire period where caller ID existed in the U.S., I can only think of a single person who screened their calls in the way you've outlined. (And that person also happened to screen calls from known numbers, too, so it doesn't really count.) Everyone else would screen obvious calls coming from toll free numbers (1-800, etc.), and just take a chance on the remaining unknown numbers. An answering machine/ringer could be turned off for special occasions, but that's no different than putting a cell in airplane mode or whatever.
In fact, there was an entire genre of comedy albums devoted to messing with incoming telemarketer calls during this period. Those albums wouldn't have resonated like they did if most people had been screening all unknown numbers.
In the same way mobile phones shouldn't have to worry about working with emergency services numbers as before we had mobile phones we were still calling them. In other words: it is sometimes better to do things that weren't done in the past.