Not really comparing like to like there.
I've got memories of the old Orlando airport, and fuzzy as they are, I can clearly remember how it was bursting at the seams- total wall to wall people, security lines all the way around the concourse because they were too many people and so little room to screen them.
At the time they got approval for a new terminal, they were already handling 5 million passengers a year. Panama City-Bay County sees something like 400,000.
As for Atlanta, there was a clear need for a major transit point somewhere in the Southeast at the time. Now, I'm not sure what PC has to offer that isn't already being handled by existing airports and ports. Tampa and Miami are huge, well-established ports serving a lot of Americas business. Atlanta, Miami, Memphis, Louisville, etc. handle air passengers and cargo.
Where's the underserved need? What can Bay County do that Miami can't?