Back when I used to drive regularly, I would listen to podcasts. One that I particularly enjoyed was the Fall of Rome. The link is to a website where you can listen online. It is also available on podcasting apps such as Castbox. Patrick Wyman is the author. He is a historian that did his research on Rome. It is worth the time to listen to the entire series from the beginning.
After Borepatch's last post, I wanted to make an observation and it comes out of the information in the podcasts. What happens to Rome as it is collapsing is systemic. It has little to do with what is going on in the government directly. The height of Roman power ensured the roads were safe, both from criminals and from outside barbarians. As that power waned, the risk to shipments of goods grew. Trade declined as businessmen decided not to take the risks.
That must have been a last shipment of wine and olive oil to Britain. No one would have known it was the last. But it would have been more dangerous therefore requiring more armed guards, more fines and fees would have been paid to traverse what a few years before had been open roads, and the roads would have been in need of repair.
And when no more trade, people, or military came from Rome, what then?
That collapse of trade around the empire meant the end of movement, the end of news from Rome, the fragmenting of the language that resulted in communication becoming difficult and then impossible, and the isolation that led to the formation of small independent states. There is a tipping point where it was going to become impossible to recover, but it began with the Roman government's inability or unwillingness to keep the roads and cities safe for commerce.