I think a big difference between modern and ancient society is that modern society really doesn't need the skills and knowledge of the economic elites.  Minus a few examples who tend to become celebrities thanks to their incredible accomplishments, Pretty much across the board, they are dumber and less competent than the striving middle class beneath them.

In the past, a massacre of the elites would result in the more or less complete collapse of a culture and a civilization.  They were the ones who could read, who had studied stuff, and who had the social skills to (in theory) keep things going.  Without the tiny group at the top, you'd have a mass of marginally educated townspeople, and illiterate and more or less neolithic peasants.  Sure, the people would survive, but it wouldn't be anything recognizable as civilization.  Post-Roman Europe comes to mind.

Nowadays, it would merely be the lifting of a parasitic rentier class.