Maybe the technology was "balanced", but the society certainly wasn't. It relied on continual expansion and devolved from a republic into an empire along the way. When the empire couldn't expand anymore, it collapsed and fragmented.
I also don't think their technology level was stable. IMO, they were only about 200 years away from developing a useful steam engine and kicking off their own industrial revolution. They knew the principals, they even had toy steam engines. They were already using both water wheels and windmills to do work when available. They were just missing precision manufacturing techniques to make a steam engine that actually did useful work.
That's the point. They had sustainable and clean technology. It was a sweet spot.
They also deforested large sections of Europe for fuel (especially to make charcoal for smelting iron), building materials and to clear land for crops. They didn't really practice much in the way of sustainable forests, unless they ran into local shortages of fuel wood.
> Roman-era mining activities increased atmospheric lead concentrations by at least a factor of 10, polluting air over Europe more heavily and for longer than previously thought, according to a new analysis of ice cores taken from glaciers on France's Mont Blanc.
A lot less than modern technology manages, but a lot more than nothing. And that with a much smaller population.
https://phys.org/news/2019-05-roman-polluted-european-air-he... https://en.wikipedia.org/wiki/Ruina_montium
53 million amphoras... That is ceramic containers chugged to a pile... Not exactly sustainable or efficient choice either. Well there is lot of clay, but still not exactly sustainable approach...
Just curious whether I'm missing some connection.