The Seabee is one of those classic designs that hit at exactly the wrong moment in history.
A few years later, people realized that amphibs were really good things to have in a lot of places, more efficient, spacious and fun to fly than planes with floats tacked onto them.
Republic developed it as a way to keep the production line running between the end of P-47 construction and the acceptance of their first jet, so they really didn't have the same kind of dedication to it that might have made it more of a success.
A similar thing happened with the Navion -- when North American didn't see the expected explosion in civil sales, they were happy to sell the design to Ryan, and stay with military airframes.
I know of one Bee which found its way to the Philippines, then to South Korea, where it got log entries (in Hangul) such as "8 landings (water), 3 landings (land), 11 water takeoffs, patched left wing 4 places." A very versatile and capable plane.