I think the promise of SMR is that the 1/5th reactor can be built in 1/2 the time. And you build five of them in parallell. And you have your power sources gradually online over about the same time as one ”big bang” build would take.

I don’t think it’s going to work out that way, but that’s how it’s being sold.

Even like that, it is not clear-cut. 1/5 in 1/2 the time is still 2.5 shorter per worker, and building in parallel require multiplying expert builders, which is not easy (as it takes time to acquire the expertise and you don't want to learn a trade to build one project and have nothing to do next).

But, yes, I get it is how it is sold. Just that even sold like that, people with common sense should say "wait a minute, that's obviously not that simple".