In "family use," we have found that the first thing to "break" in most phones is the charging circuit. The device gets plugged in in living rooms, bedrooms, cars, etc. and eventually some part of the connection becomes compromised from some sort of physical abuse. It will be nice to not have to worry about that.
Backward compatibility is highly overrated and most of those old phones are going to become e-waste after 3 years or so anyway. If you consider the costs of "vampire power" from wall chargers that are plugged in nearly 24/7, is it such a bad thing if those become e-waste too?
Few years down the line when almost every users start to use wireless charging devices, what happens to the billions of mobile devices? Any plans for making some kits (like the battery kit capable of wireless charging) for enabling the old phones to be able to adopt to wireless charging? If not, then what is the plan? Turning the old devices to e-waste? Even though, the increasing trend of getting bored with our phones in a couple of years and then changing over to a new one is already generating a good amount of e-waste, with the onset of wireless charging, the e-waste might increase multifold when people start throwing their chargers too. Any solutions to that? How is the standard for "universal" USB charging evolving?