Well, history until now has favored revolutions over electoral campaigns.
Can't say I agree with you there. The USSR collapsed, China had backpedalled into private enterprise, the revolutionary states that haven't collapsed have hardly brought about international communism.
the point is that it is imperative and inevitable that they need to consolidate their power or else no socialist project can outlast them.
Except "they" is going to include a lot of dark triad types. Consolidating power is only good if you can trust the people you've consolidated it in. Untrustworthy people are drawn to power, and they're willing to lie and plot to get it.
Socialism is by definition a transitional period between capitalism and communism
Socialism is by definition worker ownership of the means of production. If soviet workers didn't have democratic control over their production, it isn't socialism. They may have been aspiring towards it, and a noble attempt it was, but they drifted pretty far from the goal.
The whole point is to gradually transition into communism without disrupting citizens' livelihood
Which is why reform seems the obvious choice. Any revolution is going to bring chaos and suffering, as well as a potentially slippery power vacuum. What happens when your revolution successfully topples the government, the corporations, how do you coordinate production and distribution? I don't mean eventually, I get eventually, but day one after the revolution how is society going to work?
Even if you have the perfect theoretical system ready to go, you still have to implement it, and that takes time. That's a lot of disrupted livelihood.