I guess we just disagree on when the next war will be then. I'm almost certain the Cardassians will attack before 2316 is over. Once the moratorium ends and we start taking in new members, we start growing far too fast for them to keep up. If I'm right, if we don't build a Starbase this year, then it'll still be under construction when the war starts.
It's extremely meta, but Oneiros has indicated he wants us to have a period of peace after the current war. Of course, no guarantees, but I think you have to look to the Cardassian shipyard push rather than our moratorium. Their shipyard push will start launching cruisers in 2318-2319. That's when I expect the Cardassians to strike.