Grasshopper mowers are definitely not cheap and outdated. They may have a boring, outdated paint scheme, but the mowers themselves are very popular with lawn care pros that put several hundred hours per season on their equipment. Those guys rely on their equipment every day, so reliability is important, which says a lot about the build quality of Grasshopper mowers. I see a lot of them on lawn service trailers around here.
You don't see many of them being used by Joe Homeowner because they are commercial quality machines built to stand up to professional use, not built to a price point to entice the bargain shopper.