* Assuming you were 100% correct, that means it's a rate problem. Assume it takes time X for bacteria to evolve resistance and it takes time Y for us to develop each new antibiotic. As of now, X << Y, but Y is falling. Once Y < X we are developing new antibiotics faster than resistance is evolving, it's basically a solved problem.

* Fitness is not a 1-D line. Every time a bacteria evolves resistance, it pays a cost for doing so (in lab experiments it's pretty easy to generate resistance by adding antibiotics, and the resistance factors disappear very quickly once the antibiotic is removed, suggesting a fitness cost). So even while they're getting harder to treat they're also getting less robust in general.