My understanding of the tilt or Dutch angle is that it was increasingly used by wedding photographers when they ran out of width in their photos and couldn't fit everything they wanted into their frame. Case in point is my photo below. I was using a 24mm prime and was out of room to back up. I wanted the bride/groom & bouquet in the shot plus I wanted to give them run to walk into.
Obviously I would have preferred to have a wider lens on but you can't always have the right lens on at a wedding. Disclaimer: I'm not a wedding photog, just a guest in this case. But I know several wedding photogs and have heard this from different sources.
Getting back to the topic, I believe several people starting liking this "new" techique and started incorporating it into their style regardless of whether it was needed for space concerns. Next thing you know everyone with a camera starts doing it across all areas of photography.
As for myself I throw it in every now and then to break up the monotony of vertical portraits. I see it as another tool in my bag, similar to mixing up the DOF or using a lensbaby.