Yes, fallback is Spanish indeed. But I'm a young guy, I got to clubs a lot and most people I meet there are between 20 and 30 and having very hard time speaking in English. Which makes me amazed, especially in Barcelona, which is a very international city. The same problem is in France. It might be due the fact that most of the media never displays any English. Movies are over-voiced in Spanish and so forth. I have no sources to back this claim, it's just my theory.
Yeah, it's interesting how just having subtitled media can help. When traveling, I came across an older guy in Viljandi who had learned his basic English from watching Melrose Place reruns.
For political and historical reasons that don't need to be discussed all over again, many people are bilingual but make a point of writing, speaking and demanding Catalan. They might be resigned to Spanish-speaking tourists, but much less tolerant in more official contexts (like software localization choices).