Yes; many resistant bacteria already exist, including to cipro. Some bacteria however are more likely to become resistant than others, for example Staphylococcus aureus develops resistance especially quickly, and is also among the more concerning pathogens, especially as it's an abundant member of the normal human microbiome, and can therefore be exposed en masse.Thanks for the clarification.
For the record, I presume the resistant bacteria is already out there and it remains to be seen, with time, if it will become dominant in the ecosystem or if the weaker ones will prevail even with their susceptibility to antibiotic treatments?
But all that aside, the less we dump into the environment the less we will have to clean up later, if we even can.
It's a race against natural selection at the end of the day. We can't stop it, short of driving the bacteria to extinction which is also bad. As long as a species exists, it can mutate. All we can do is slow the process down, which is still an extremely important means of defense as it buys us time to develop new treatments.
The less resistant bacteria that enter the environment, the more likely they are to be outcompeted. Larger microorganisms of all sorts feed on bacteria. We'll never be permanently defenseless, but lacking a swift response even for a short period can be devastating