These two things are not incompatible. Yes, antibiotics are awesome. Yes, we messed up because these days you can convince your doctor to give you antibiotics for viral infections (they will tell you it's useless though) and take as little as you want of it, and create more resistance problems.

And make implants possible as well.

It means you don't die when you go into surgery, you don't die from burns, you don't die from severe bone fracture, and cancer is actually treatable.

Chemo and radiation therapy tend to reek havoc with the immune system, certain types of cancer leave you with little to no white blood cells period.

Without antibiotics you could not have these treatment regiments at all as without preemptive and reactionary antibiotic treatments many cancer patients would die.

Without anti virals and antibiotic other conditions with compromised immune system including HIV would be considerably more fatal as well.