I would say that well over 90% of fiction shows end without any closure. They just disappear.
Some shows, like both Stargates havefinal showsthat indicate ending, but leave the story possibilities open.
Then there are shows like MASH that do a more in depthending with finality.
I just finished watching what was to me the best in depth ending I ever saw. The show was Arrow and it actually kinda moved me a little, and I am not in the habit of being moved by fiction shows. Really gonna miss that show.