I think television has similar tropes depending on the genre but overall, there seems to constantly be a push for something more modern and more unique than the show before it. Just because a lot of shows are returning that previously ended doesn't mean that the majority of shows are doing that. Television for nostalgic purposes is not necessarily bad because there are different kinds of audiences that are reached that way that aren't reached by new shows.
Television has not become too nostalgic. For instance, there are many new programs that focus on superheroes. These are aimed at adults. One example is the show Gotham, based on Bruce Wayne growing up and covers topics show as the mob. Netflix has innovative series, including Orange is the New Black.
Television shows today are nothing like they used to be. When I think of television being nostalgic, I think of old shows being played frequently or recreations of old shows. There are only a few channels that play older shows, especially the black and white older shows. The shows that producers are coming out with days are new and creative and are far from what television used to be.
In fact, television is anything but nostalgic. The days of entertaining sitcoms such as I Love Lucy, Bewitched and The Beverly Hillbillies are gone forever. Likewise, variety shows such as Carol Burnett and The Ed Sullivan show are long gone. TV now consists of useless reality shows and inferior programs.