@dragosroua, thanks for the detailed explanation... it's really the perfect response to my question-post from a couple of days ago. It's nice to understand how the underpinnings of Steemit really work.
A semi-newbie question: The fact that these "drop outs" are happening more often, is that the result so many new members, so many more transactions? Would it be solved by adding more witnesses, or is this issue not related to overall network capacity?
It's a process of adjusting. Increasing block size also helped. I don't see it quite often lately so it means the network adjusted.