Summarizing the Third Century Crisis

[SigniferOne]

For what it's worth, I believe the key to the so-called Third Century Crisis was the coincidence of barbarian invasions, natural catastrophes and civil war amongst usurpers, which exacerbated financial difficulties by disrupting the economy.

Another Marcus Aurelius or Septimius Severus could probably have weathered the storm. You can see things picking up again under Aurelian, so it was just an unfortunate episode rather than a trend.

But then Diocletian took a more authoritarian stance, which has coloured our view (imho), encouraging us to see a continuing process of decline.

Nevertheless, the cultural decline was present since the 250s if not earlier, so long before Aurelian. It is pondersome if Aurelian could have stemmed a collapse of the entire culture rather than just some military incursions on the border; but either way Diocletian came shortly thereafter and put the last nail in that coffin, as you said.