Personally I stopped upgrading my gaming PC about 5 years ago and I just don't see myself ever getting back into it, at least in the way I used to do it (every 2-3 years upgrading the CPU and GPU, and inevitably the MB, memory and hard drive because I like to play the latest games and "good" settings are never "good enough" for me. I'm also a huge fan of playing on my TV and personally love controllers vs. keyboard/mouse. While I love the PC mods I hate the PC cheaters, hacks, viruses and malware. For me, buying both PS and XBox makes more sense (I bought a PS3 & 360 last gen, I bought a PS4 and am about to buy an XB1 for this gen).
What might change everything for me is the Steam box though, in particular the Alienware box. We don't know how much they're going to cost really yet, but 99% of what I don't like about PC gaming can be summed up in one word: Windows. With Steam OS there is no Windows, and while I honestly wonder if we'll see all AAA games ditch DirectX and switch to OpenGL/Mantle etc. so they can run on both Windows and SteamOS, it just might happen. If it does, and the price for a decent (Alienware) Steam box is somewhere closer to $400 and less like $1000 then yes, I'll probably get back into PC gaming again.