You're definitely onto something. I don't know precisely what the mechanism is, but I've also observed the 2000'ish threshold.

I think it has to do with catching the right people's attention and eliciting the higher zaps that some big rollers are willing to drop.

It's still a small community and there's a wide range of how each of us zaps stuff. It's almost an entropy type situation: there are many ways to get to 2k sats, but only a few ways to get much higher.