Is it gouging? Yes. Are we going to do anything about it? Probably not. Why? If we try and cut off NW for lower fares, whoops there goes NW to Detroit, along with all the jobs and nonstop flights. And we realize that indeed if it wasn't for NW we wouldn't have the number of jobs and nonstop flights that we have. The Twin Cities simply isn't that big, it's way out of proportion when it comes to the airport's size, flights, jobs, everything really.
Heck it seems like if the fares to Florida are good then the majority of people in the Twin Cities are happy enough with the way it is.
Don't get me wrong, I hate being gouged for tickets, but that's simply the impression I get of how it works at MSP.