It's just too expensive to game on a PC. You need high-end shit, and keep upgrading it. Plus you always have the occasional bugs that come up and mess up your experience.
I am still gaming on a PC with a motherboard from 2006 and a graphics card from 2008 (GTX 280). I can run even the new stuff in medium to high detail at 1080p. I'm doing a hardware refresh when the CV1 comes out. It's not the late 90s / early 00s anymore bro. Your hardware lasts longer. I really wanted to buy new hardware earlier too but I couldn't justify it due to the great performance I had in my games. Now I am just holding out for the Oculus Rift before I build my new monster rig.
Like people also said. You can get a decent gaming rig going for under 500 dollars if your budget is truly tight, and steam sales are much cheaper than buying games for a stupid underpowered console.
Also what makes you think you'll have to upgrade your PC constantly if there's the underpowered game consoles that act as a lowest common denominator? These days games are designed to be quite scalable depending on your hardware specs.
There's of course a lot of PC exclusive stuff out there too now, but they usually don't push systems except maybe Star Citizen. We're very much in a PC gaming renaissance right now.