I've always thought the same thing. There used to be one right by the bridge about 30 years ago. Unfortunately, the land, frontage and docking space is so expensive and hard to get nowadays that I don't think it will ever happen. There is the old Zach's at Jay's Marina. I haven't been there yet but have heard that they have good drinks. I always thought that the market next to the marina would have been a good place for an ice cream/fried food place due to the close proximity to a major roadway and a fair amount of boat docks, but the marina bought that place last year. I think that when it comes down to it, the costs of operating an establishment like this are so prohitibive when you consider that the lake/sandbar is really only "crowded" for 2.5 months out of a year.
Now if we can convince the ice cream man on the pontoon boat to start delivering take out to the sandbar maybe that's a good enough alternative.