Couldn't the same result be accomplished with commodity GPS trackers, which don't require any iPhones?

Requires more battery, clear sky views, etc. The benefit of AirTags is that the sensor network is terrestrial and the energy and comms requirements are offloaded to the sensors.

Sure, but it seems good enough for practical purposes. I mean, in her case it would even have been enough to just mail them a $40 Android phone with location services turned on.

> just mail them a $40 Android

Try to do it yourself. You would quickly find out what it is not a reliable method.

And AirTag costs $30 or even $25 each in a 4 pack.

Right, it's certainly cheaper, but my point is it's not a fundamental game-changer - she could've done it 5 years ago with the technology we had then, too.

There comes a point where a difference in scale becomes a difference in kind.

With AirTags, I think we have reached that tipping point.

Well, duh, she could just travel in time to say her past self to do it then.