You can't deny Glee's impact and the talent it cultivated and introduced to the world.
However, I would argue that it was High School Musical that was the catalyst for brining Musical Theater back into Pop Culture.
That Disney Chanel movie, now 20 years old, was HUGE in terms of merchandising, an arena tour, an ice show, and music sales. They even had to create a stage show so schools could license it and produce it.