I didn't really say my opinion as advice. It's just my personal preference backed up with the reasons taking a cab or renting a car is better for me.
But if as you said, everyone took my advice and started taking cabs, yes that would be a problem too. It's just a good thing that lots of people do what I normally do and rent a car, while many countless others are first or second timers to CZM that haven't had the good fortune to locate Scubaboard, so they don't know there are alternatives to accepting the very expensive hotel transfers that are sneeked in to their total bill when they book.