I mean, the main social institutions that underpinned all the others in Rome were massive human trafficking and looting operations. The enlightened Greeks weren't any better.
My personal guess is that we would've had the industrial revolution thousands of years earlier if these groups we like to glorify in our history books would've laid off the enslaving, murder, and robbery.
I'm not saying the Greeks and Romans didn't have any merits at all. Can we learn some things from them? Sure. Do we have to call them 'great,' and aspire to be like them? Absolutely not.
Life in 700 AD was completely different from life in 1400 AD. Cities, population density, building styles, international trade, weapons and warfare, agricultural methods, secular institutions - almost nothing stayed the same.
People tend to even forget that the official definition of "the Middle Ages" stretches back into the Dark Age, where kings were more like chieftains, castles basically unknown, even most of the clergy struggled to read and write, and a typical member of the elite warrior class looked nothing like a stereotypical knight.
Romans built blocks of dwelling houses 5-6 stories high, houses with central heating, and running water delivered to their cities (and wealthier homes) by systems of aqueducts and pipes, etc. These are things that we associate with 19th or even 20th century in large parts of Europe.
Sadly, their social institutions, even as famous as the republic, were also not practiced and even forgotten for long centuries. Much of the Enlightenment was fueled by re-reading and re-understanding of classic Greek and Roman works, which felt fresh and mind-expanding at the time.