There is a great deal of myopia in this thread, as well as a scope issue. But most fundamentally, there is a misapprehension of the nature of art.
Let's deal with the scope issue first. Shows that do something great are not a trend. Shows that have innovative marketing are not a trend related to the art form. Shows that have innovative ways of selling tickets are not a trend related to an art form.
Art, by its nature, evolves rather than changes on a dime. Being the first show to employ a particular instrument or style of music doesn't mark a cliff that everyone dives off of, but it may mark a broadening of the available toolkit for artists. The OP used the right word: trend; others here are myopically focused on game changers. When you do all of the great things a show like Hamilton does, you don't erase what came before, but you can push certain things in the direction of going out of style. You can also raise the bar.
Technology is more susceptible of creating game-changers than art. Thus, the advent of computers really altered the way theatre is made. Late in life, Abbott was asked what the most important development in his lifetime was. His answer: the invention of the electric light.