Like I said, I have lived it. The people profiting from the "tourism" are not locals for the most part.
I also question your numbers. Not saying you didn't see them somewhere, but their is no normal statistic for "tourism". There are industry codes, like real estate/rental and leasing, professional services, food service, etc. You would have to assign some portion to "tourists" How do I know if your staying at a hotel your here for tourism, or your fulfilling a contract at the port, Volvo, MUSC, Boeing, Nucor whatever? Never trust data you haven't manipulated yourself.
No doubt people getting rich off tourism in Charleston, but only a few, and not local. The largest industry in Charleston is Health care (the states 3 largest hospitals are here, MUSC, VA and a private system - many people in the state come here for complex care. Followed by manufacturing. We have the second largest port on the East Coast. So no, we wouldn't miss it for the most part. I am sure some property managers and corporates would.
For what its worth, I don't have an issue with someone owning a second home here and living here seasonally. I really don't consider them "tourists", more like part time residents. They do push housing prices up, but its not the same level of problem.