It seems like a solution in search of a problem. By the time 3 years has past the machine should be obsolete unless we are in for another 10 year halt in progress through Intel scuffing their feet.
I'm not at all sure that is true.
Unless you just *have* to have the very latest technology, the progress that has been made in the way of processing has been modest over the past decade, in a pragmatic sense.
Before everybody gets on me, consider what most people use computers for. Even processing that is twice as fast as was a decade ago is kind of lost in many cases. Does it make email better? Web surfing? Word processing?
Certainly, if your job or serious hobby is processing intensive like editing videos or compiling hundreds of thousands of lines of code, then the improvements are worth it and can even pay for themselves. But, for most people, maybe not.
Over the past decade the biggest improvements for most people have been the use of SSDs - very noticeable improvement in actual use - and better displays like the Retina display. For laptop users, longer battery life is obviously important, too.
But, we're reaching a point where the pragmatic improvements have slowed down a lot.
What this AppleCare thing does allow is for people to consider spending more on a larger screen or something like that since they have a better feeling that six or however many years down the road, the computer will still be usable. Yeah, maybe not as snazzy or as fast as a new computer, but perfectly serviceable. It's like cars. You don't *need* a new car every two years to get yourself around.