Well, assuming matchmaking works, you're grouped with people your own skill, hypothetically, so you're likely to be placed with low-level, low-skill guys at first, just like when you first fire it up. And even with that said, no, there's still plenty of idiots around (assuming that's kind of what you're asking, too).
I took like two or maybe three months off and came back and had some of my better games. Sometimes not playing actually makes you a little better than the all-the-time guys, because you're not just going through the yeah-I-play-five-hours-a-day motions; you're in "yeah, fuck yeah I wanna play this" mode.