The main reason people don’t see them is they are not really looking. A typical day out photographing and at least once someone will ask if we have seen any alligators.
Many times we can just point (we don’t it would make us rude, but we could).
They’re not looking to do a person harm, nobody gets eaten, they just are there. Floating around looking like ‘swampy stuff’.
The image above is a good example. In the shade, covered with ‘stuff’, and just doing nothing. They blend in, which is why they are still here after millions of years.