Romans were not great economists

The history of Rome is a slow transition from a limited government to tyranny. But military centralisation worked better than economic one:

• During Cesar's time wheat prices were fixed and wheat was offered to people in Rome for free. 1/3 of Roman citizens were supported by the government. 
• All emperors (with few exception) debased the currency, paying for public works with inflation
• Diocletian was the worst as he tried to fix the prices of all goods. It led to famine & suffering. 

Rome's economy was constantly fighting inflation, but their tools (issuing currency & fixing prices) led them to ruin.