Sankt Gilgen is not much more than a village, but it’s a quite nice one.
I suppose motorboats are limited, just like they are on most lakes in Austria. You need a license, and the total number of licenses is restricted. In Carinthia this has led to an expensive market for licenses, and having your own motorboat is a status symbol for the rich.
It’s not exactly a fair system, as it makes access to motorboats practically impossible for the average well-off citizen, but restricting the number is necessary, or otherwise water quality would suffer.
Again, this is in Carinthia, where expensive lakeside residences existed for a century. I’m pretty sure on Wolfgangsee motorboats are limited to a few businesses only.