Call me old fashioned but it’s probably deteriorating material conditions that are going to radicalise more people in the long run.

Definitely true, however you're going to want a portion of the population "pre-heated" by these electoral defeats so they can do some vanguardism when the time is right. This is true even if it is stagnant and cyclical, like you propose. I don't think I fully agree myself, but I could see it.

The true revolutionary action will happen at the periphery of the empire. If some Demsocs create internal strife and discontentment in the core, it allows for more opportunities for our comrades on the ground in the more materially impoverished areas to make some moves.