It's always strange to watch genres fall out of favor. Genres never truly die, in the traditional sense, but rather fade away for several decades as they slowly gather strength for their inevitable return. For whatever reason, whenever a genre becomes popular, Hollywood doesn't just exploit it for profit; they practically force you to consume as much of it as humanly possible.
If Tinsletown was able to practice a little restraint and not flood the market with whatever flavor of the month holds sway over the populace's imagination, genres like the Western and musical might be as viable as superheroes. However, superheroes, the current genre king, are likely doomed to suffer a similar fate as other former cinematic titans.
One genre that's also faded from the limelight is the historical epic. In the video linked above, the YouTube channel Scene It Reviews explains why the historical epic went the way of the dinosaur.