That is supposedly what happened with Rome. A very modern society (by our standards) was replaced by barbarians (by our standards). Those barbarians eventually developed a lot of the same social and political structures as Rome.
It was a regression from a unified pan-continent society to isolated tribes. How advanced those tribes were is hard to say because most didn’t write things down.
As far as I know what followed Rome was a period of unrest and lessened commerce. From that aspect at least it was “worse”.
And it took over a thousand years for a city larger than Rome to appear again anywhere in the world. Sometimes things just crash and nothing replaces it.
It was a regression from a unified pan-continent society to isolated tribes. How advanced those tribes were is hard to say because most didn’t write things down.
As far as I know what followed Rome was a period of unrest and lessened commerce. From that aspect at least it was “worse”.