I visited Pompeii years ago. I remember it for several reasons...one is the mazing place that it is and the other being that I got the worst sunburn I had ever had on that day.
It’s seems that there might have been people who loived more comfortable lives than many but whose lives couldn’t match those of the truly wealthy.
I visited Pompei back in ‘79 - found it interesting.
An old History teacher told us that Rome’s downfall began with the institution of the Dole - to fund artists and others who gave us pretty things but produced nothing consumable....
Nearly every society has a middle-income group, I find that easier to understand than 'class' anyway. :^)
The supposed end to the supposed Roman republic led to a massive reordering of wealth without forced redistribution. Redistribution always only benefits those making the redistribution.
More people, mostly non-Romans adopting Roman ways, took advantage of a wide-open market economy that had likely never existed anywhere before, but at the very least had never before existed on that scale.
The Roman army built and maintained a transportation infrastructure, local law and order, and security from piracy and cross-border raids.