Note that essentially all modern battery systems essentially do this under the hood. The "100%" shown to the user isn't the most you could charge the cells, just as high as you want to charge it to meet lifetime degradation targets. Tesla just goes a bit crazier here and exposes more headroom because they can rely on drivers being more involved in charging strategies.
What separates drivers from phone/laptop users? Certainly not techies vs normals. It would seem to me that both cohorts are capable of, and potentially interested in, deciding between "shorter days but more years" and "longer days but fewer years."
I think the real difference is that car manufacturers' business health depends on less maintenance over many years, and phone manufacturers' business health depends on planned obsolescence.
Cars have way more capacity than they typically need, and very predictable usage patterns. If your car has 400 km of range and your daily commute is 80 km total, you can pretty safely charge to only 200 km and not get range anxiety. In the rare cases where you need as much capacity as possible (road trips), you know your approximate departure time, so the battery only needs to be at maximal charge for a short time.
Laptops don't get used like that. People plug them in, then unplug and walk around with them until they either they run out of power or their meetings are over. It's really asking too much to have people plan their usage out. Plus the draw rates aren't predictable. If I can get away with just checking email, my laptop lasts all day. If I have to do a big C++ compile that's 30 watt-hours right there.
I might also add that really only Tesla is doing the charging guidance UI. Other car manufacturers spend a lot of resources to perpetuate the illusion of a battery working like a fuel tank.
Some laptops support this too (eg business Thinkpads). Apple is a luxury brand and batteries are cheap to replace so it doesn't want to burden users to spend their precious cognitive capacity on battery management.
