It wasn't really a slump either. Consoles have been outselling PC versions for years. Since the early 2000s at least. I assume this trend goes back to the early 1990s though. Consoles were cheaper than PCs back then, less people used PCs then, and gamers were younger in those days. In the mid 90s not many adults played video/PC games. Not nearly as many as today as many of those kids who grew up playing games are now adults and still have their hobby.No, the 360/PS3 did not "take down" PC gaming. PC gaming was in a slump at the time as retail stores were starting to phase out their PC sections as consoles grew more and more popular. This was a trend continuing on from the previous console generation when the PS2 exploded in popularity. It wasn't even necessarily a case of people abandoning the PC either as much as it was more and more new people playing console games and spending a hell of a lot more money on them vs PC. Plus, its not like retail shops like Gamestop could buy and sell used copies so that meant they weren't really turning much of a profit on the games. It was also coupled with a huge rise in piracy as more and more people were getting access to faster internet and the lack of good availability for games (and the incredibly limited and not always great digital options) made more people turn to piracy. Then Steam started selling 3rd party games and the market grew exponentially.
This is partially why you see a "resurgence" in PC gaming. PC gaming has been smaller than console gaming for years and still is (for AAA games) but it is growing as gamers have more disposable income. PC gaming is still a very cheap hobby compared to just about anything else. For many adults $1200-2000 a year isn't a lot of money. You don't even have to be a huge gamer; it just isn't a lot of money and some people are okay with spending that to get the best experience possible. And realistically, that $1200-2000 goes down as the up front cost is high but you tend to keep monitors, peripherals for a few years at least and you can always sell off older hardware to make money back.
This was a large part of the reasoning for the PS4 Pro. While not a PC, there are many console only gamers who absolutely won't mind buying a slightly faster version of the console 3 years later because it is still cheap compared to other hobbies.