You can claim that every counterfactual conditional is true in some alternate world, however unstable it requires that world to be. In impossible worlds, everything is true and false at the same time, and in possible worlds, the counterfactuals that are really true have true conclusions.
The problem is that the subjunction places the statement in the realm of alternate realities and not actual reality, and without specifying which possible world you are talking about, the statement becomes true but useless.
In situations where the range of allowed possible worlds is well-defined, either explicitly or by context, the subjunctive form becomes declarative when combined with that definition included in the premises.
With this interpretation, the same is true of statements of obligation and of statements of mere potential. They are all true all the time, but only meaningful with additional premises.