Two sides I have seen:
For: Dislocated proletariat is the moving force of history that renew the dying material world. The people are the ones who create history. The revolutionaries will come between the chaos and guide the dislocated people to a better path, each time a better world.
The dishearted and unawakened must know that history is about revolution, and we walk on the path of history without hesitation. A lot of people project the duality of the present state unto the future. As to make the future uncertain. Wrong, there is only one future. The end is the past, but the future is the beginning. Therefore a true communist should not be discouraged and fall into nihlism, because the future is determined. The only thing left for us to do is fight.
Against: The future is not determined yet. A materialist or anyone who claims to be a communist will not hold this idea. It results in waiting, waiting for the time, waiting for the proletarian “wake” and have “classes conscious”. This is a kantian leftist, not a hegelian leftist. We don’t believe that there is a decided, unchanged future “waiting ” for us. The only thing it lead to is the economy determinism like Ti1. For Lenin in 1917, there is no big other can say that the revolution will succeeded. Future determines past by the mediation of subjects’ practice.
They had the surplus, but you are right they socially didn't have the conditions to create such developments. There is some debate, but they probably could have done the industrial revolution if the social conditions had stacked up. They were unlikely to stack up that way in that region at that time, but an well managed empire might have pulled it off in a better timeline.
I'm not sure they did, even 16th century economies outdid Rome as percentage surplus. They could have pushed into a guild-era economy, maybe, but the latifundia would have crippled local capital development in the same way it did in the slave economies of the Americas. Until that was resolved the society could not progress.
That said they had shit like fractional reserve banking so maybe something might have been done in the Second Century before things ossified.
Sounds like you are better informed than I am on the subject then. I'll try to read up on that more then.