The world today is inundated with superhero adaptations. After a while, the cliches become tired, the storytelling gets repetitive and it's hard to break new ground.
This was exactly the case in the late 1970's and early 80's, which gave us live action versions of Wonder Woman, Shazam, Superman, Spider-Man, the Incredible Hulk, Captain America and Doctor Strange, among others.
So along came a show that exploded the tropes and did "superhero in the real world" stories long before the Nolanverse. The Greatest American Hero is a parody, first and foremost, but if you look past this you'll find some truly great storytelling and great performances (Culp as Bill Maxwell is a great example). Highly recommended.