We don't need to develop an antibiotic that's impossible to gain resistance to. We just need to stay ahead of the cat&mouse game, which can go around in circles

We don't need to develop an antibiotic that's impossible to gain resistance to. We just need to stay ahead of the cat&mouse game, which can go around in circles. If we start using a completely new type of antibiotics and stop using the old ones for a century, bacteria will gradually lose resistance to the old ones as they gain resistance to the new ones.