The two most common factors that hold people back from switching over to a PC gaming machine from a console is the initial cost, and often times the technical aspects. The initial cost of a PC is always going to be more than the initial cost of a console. I would argue that an Nvidia GTX 950 or AMD R7 370 would be a good "low-end" starting point for graphics in a gaming machine, and both hover around the $150 dollar price range. That's nearly half the cost of a console in it's entirety, for just the graphics card. Pair that up with a quad-core CPU, a 1TB traditional mechanical drive, 8GB of RAM, a decent motherboard in an average case and you are looking at the $450 to $600 dollar price range. That kind of a price tag kind of turns people off when they simply think of the machine as "just for games," like a console. But when you realize that you can do schoolwork, create programs, write papers, browse the web, stream videos, listen to music, load up any Windows or Linux operating system that you want, the PC becomes much more appealing, because it's a multi-use device and thus becomes worth the investment.
The technical aspects of gaming on a PC also turn people off. While not nearly as difficult as it once was to run games on a PC since the advent of Steam, you do occasionally run into a bug here or there, an older game that won't run that necessitates fiddling around with a config. file of some kind or messing around with compatibility settings. On a console, it's just plug and play. Most people have the technical know-how to solve problems such as these, but for the incredibly computer illiterate crowd who just want their games to open, run, and close flawlessly every time, the PC platform presents a problem. It's getting better, but it will never be perfect. I always encourage people to take time to learn about the platform and how to troubleshoot. Being able to gain knowledge about the PC and the operating system to troubleshoot issues will help with troubleshooting further problems in the future.
The aforementioned two issues are becoming less and less of a problem, as people are becoming increasingly fed up with consoles high games and media costs, pay to play systems, and not so impressive graphics and CPU horsepower. While older consoles such as the N64, PS2, and GameCube will always have a place in my heart, no systems newer than the 360/ PS3 era consoles interest me in the slightest. More and more people are becoming disenchanted with the new consoles, thus the latest surge in PC gaming. In addition, I feel more people are interested in building their own gaming machine, as people have finally realized that it's really not very difficult to do so. You just have to do a little bit of research and match up the parts. The customizability and modularity of a gaming PC are also incentives. You build a PC and it runs games fine for three to four years, but you begin to realize that you can't run the latest games on the higher settings at reasonable frame-rates. What do you do? Upgrade your graphics card, or turn down your settings slightly. You don't have to necessarily purchase an entirely new system just to play the latest games. In addition, no other platform on the planet has backwards compatibility that stretches as far back as the PC. I still play DOS games on mine... MechWarrior 2 has a special place in my heart.
The culmination of these factors have resulted in an awesome increase in the amount of people gaming on PC's. I do think that we are currently headed back to the 1997-2002 peak of gaming PC use, and are entering another "Golden Age" of PC gaming.