JMich: I don't. I seriously don't know what's the difference where the current generation of consoles is involved.
If you compare XBox to XBox 360 to XBox One, then yes, I do agree that they are different consoles, but they are different ones, not same consoles. It's like comparing Gameboy to 3DS.
So seriously asking, how is it different? Not a bait.
Alright then, I'll humor you. I buy an Xbox 360 on release. Then Microsoft decides that it's not powerful/robust/stable enough and releases the S. I, as an adopter of a new generation of consoles, am royally fucked. Someone got the better of me, at a better price probably, because I just couldn't wait to give my money to Microsoft. In this example, I'm only going from original to S. Do you know how many versions the Xbox 360 has had?
https://en.wikipedia.org/wiki/List_of_Xbox_360_retail_configurations This many.
We're talking about consoles, not PCs. You don't buy a console to have to upgrade it. Quite the opposite in fact.
Sure, you don't HAVE to. But you're fucked either way. You're stuck with inferior equipment, on the same console generation, unless you are willing to dish out more cash to Microsoft. Or Sony. And about those games that "are compatible with any of the current generation consoles" well... that's utter crap. Games run better on better configurations. New releases are going to take advantage of that extra kick in power, you can bet your life on that. And you, with your lowly first edition, is going to be left with your dick in your hand, wondering why that new game stutters that much?