I originally was very much a console-only gamer. Growing up, internet was usually slow (we were dial-up still long after others switched to something else), but we had decent consoles and games. I bought my first DS Lite in college and was a big handheld gamer during those years. At that time, our home PC wasn't very powerful, so the few games that I was interested in back then wouldn't run very well, if at all. I do recall playing The Longest Journey, the Sims, Fallout 1, and an emulated version of Earthbound back then, if anything.
I had no idea what Steam was until a friend bought me a Steam game. From there, I appreciated the easy matchmaking functionality as he and I fumbled through other free software trying to find a way to play Borderlands together.
At that point, I was only occasionally playing games on my Xbox 360, though that was mainly Rockband and Guitar Hero. The PS2 was still kicking, thankfully, so I remember enjoying kicking back with a few hours of Persona 4.
After a while, as Steam became more and more ubiquitous, I found myself accumulating more and more PC games.
I think I still prefer the console experience, but I love that more and more developers are able to self-publish their games now through Steam. Consoles get that as well (I remember the early days of Castle Crashers and Limbo), but it's bit of a delay now usually between the PC release vs. digital console release.
But yeah, as others have said, there are many reasons for folks to prefer one platform over the other. Perhaps they have a PC with decent specs or they really like mods/modding. Someone else might prefer console because they don't have a great PC or they just prefer the living room experience. I definitely go between the two all the time but probably prefer the console at the moment because our gaming PC is decent but probably couldn't beat out what the PS4 currently can do.