I think you’re right Yves, and I also think Umair is too.
It’s a signal to noise problem. Twitter does a terrible job of getting what you have to say in front of people who want to hear it. So you feel like you’re “tweeting into a vortex”.
It also explains abuse. In a landscape of white noise (ie lots of low value signals), the signals that stand out are the ones that hurt. I’m not particularly popular on Twitter, but from a hundred replies, the ones I remember most vividly are almost all mean ones, and a couple really nice ones. We’re just programmed to be more sensitive to pain. So abuse leaves a memory.