Basically, what it comes down to is: In my heart of hearts, I just don't believe that a revolution will happen in my lifetime, even if I live to be an old-ass man.
So if I were to just go all-in on hoping for revolution as opposed to anything electoralism-related, in my brain, I'd pretty much be admitting to myself that I personally won't live to see anything get really significantly better, that when I die everything's still gonna suck or be even worse than when I was born.
And I guess I just can't bear to admit that to myself.
The middle ground between wimp electoralism and larp revolution is building class power through institutions composed of working people that act to enhance the conditions of working people and through such success grow themselves, as I understand it. Those can helpful in the event of either a bourgeois election, where they might be able to get you Bidens instead of Bushes, or a revolution, where they will form the power base of the left.