In 2004 we were on the Magic after the 2 previous cruises were changed due to storms. PC was closed for several weeks..
As were all the ports in Florida two weeks before our cruise. Cruise lines can not just ‘choose’ to stop at any port that is nearby (except perhaps in a real emergency). There are many things involved including port fees, what other ships are due in, the size of the port and the size of the ships that can be accommodated. Tampa is a relatively small cruise ship port that is located well up a river/canal. Many of the current ships from different cruise lines are unable to port there.
Port Canaveral can port as many as 5-6 very large ships. I do not believe that Tampa is equipped to port the larger ships or nearly as many.