Final answer:
Fluoroquinolones are not widely used due to antibiotic resistance, serious side effects, and the time and investment required to develop new antibiotics.
Step-by-step explanation:
Fluoroquinolones are not used more frequently due to several reasons. First, the emergence of antibiotic resistance has limited their effectiveness against certain bacteria. Second, fluoroquinolones can have serious side effects such as phototoxicity, neurotoxicity, cardiotoxicity, and increased risk for tendon rupture. Third, the development of new antibiotics takes time and financial investment. These factors contribute to the limited use of fluoroquinolones in medical practice.