I disagree. I've seen teamwork and tactics executed clumsily but effectively in the 4s, and done well plenty of time in the 3s. Which is not to say that it is as common and done as well as in the P12 or masters races, but it's not that uncommon. You haven't raced in 15 years, things could possibly be different than you remembered.
It's like saying breaks don't work in the 5s or 4s... that may be true much of the time but it's not universal.
Maybe I should be more specific. While there
is teamwork present in 3/4/5 races, it isn't as strong a deciding factor in the outcome of the races as it would be in P12. I'm with WR on this in that a single rider can easily overcome the teamwork in 3/4/5s, but very, very unlikely in P12.