In my experience, no, that's not very common. But a lot of things on E come in cycles, flurries of interest being one of them. Sometimes people flake, yeah, but they've usually got a good reason for their behavior even if they don't share it with anyone. RL has a tendency to swamp a lot of us from time to time and it sucks, but if someone can reduce a little stress in a hectic day by just dropping out of a forum or PM game for a little while, I'm not going to fault them for it. Remember that now's around the time a lot of schools are doing their final exams and projects and stuff, so you may have just caught a lot of interest from students who realized they didn't have as much time as they hoped for another game.
Elliquiy has been around for eight years, and it's resilient enough to go on a lot longer than that. I'd suggest just widening your search for partners and games, and you'll find plenty of awesome players that you'll gel with.