That’s not the case- an incomplete theory breaks down at some point, but it still has explanatory power. BBT has a lot of evidence, and we’ve made a lot of predictions using it that have been proven. Of course, you’re still correct in saying that JWST has shown numerous discrepancies, but that shows that it can be superseded by a better theory- an analogy would be Maxwell’s equations are good for most situations, but QED is the more complete theory that works even when Maxwell’s equations don’t.