There are some schools which are hiring people with experience, who they then train to teach in various ways while they get on the job experience. High School High is the most famous and probably the best, but that model is being put into place elsewhere as well. They hire based on what skills the applicant has to offer, and offer training for several years after. It’s not the norm of course — in fact, a lot of long time teachers found themselves facing the same roadblocks you mentioned when states began to try to “standardize” certification requirements. They’d been teaching for years, but were suddenly forced to either go back to college or quit. But new models are out there, made necessary not just by the teacher shortages but also because kids learn so differently now. There’s not enough of that yet, but there are districts who’ve had success with it.