I have a fairly old (read ancient) computer, but X3 works just fine with it. I get the feeling that someday soon an upgrade will come along and my computer will scream "ENOUGH Already", and I'll be up for a new computer. That means the price of a software update and the price of a new computer. I'm sure there will be other programs I'm running that won't work well with a new, updated computer, so there's more cash to be splashed.
Fortunately, or unfortunately for Cakewalk, X3 is such a usable, solid piece of software, that I'll be more than happy to stick with what I've got, and an upgrade won't be happening till the computer actually breaks down. Of course there will always be the possibility that there will be some part of X4 that I can't live without (read Hovercar) and I'll be forced to raid the retirement fund to update, but it will have to be some deal breaker for that to happen.
You're reading a post from a musician that only ever uses a couple of dozen track to record audio and nothing else, so a bigger better DAW is not such an issue. Every now and then I'll add some EQ, a compressor or two, then some automation and the odd synth part. I'll put on a Console emulator on every track, then add TH2 to give the guitar some bite, back up to Gobbler and then....Oh No wait, overload.