Rome\'s 3 biggest mistakes.

[Epictetus]

the conservative attitude of the Roman elite, which did not like risk investment

Senators, of course, were forbidden to participate directly in some risky investments by the Lex Claudia.

He was also odious to the fathers on account of a new law which Quintus Claudius, tribune of the people, had carried against the senate, Caius Flaminius alone of that body assisting him, that no senator, or he who had been father of a senator, should possess a ship fit for sea service, containing more than three hundred amphorae. This size was considered sufficient for conveying the produce of their lands: all traffic appeared unbecoming a senator. This contest, maintained with the warmest opposition, procured the hatred of the nobility to Flaminius…

Livy. 21.63.4.

Dion went a step further to make good hard work derogatory. He claimed only agriculture and warfare were honourable.

[Romulus] appointed slaves and foreigners to exercise those trades that are sedentary and mechanical and promote shameful passions, looking upon them as the destroyers and corruptors both of the bodies and souls of all who practise them; and such trades were for a very long time held in disgrace by the Romans and were carried on by none of the native-born citizens. The only employments he left to free men were two, agriculture and warfare…

Dionysius of Halicarnassus. 2.28.

Official policy certainly didn’t encourage the most efficient use of labour or capital. That was certainly a major problem.