What was the reason or reason's for theatre's downfall?

I recently read Arthur Miller's Memoirs in which he mentioned how when 'Death of a Salesman' was on Broadway, it showed to full houses every night, and he was making about $20,000 a week in royalties. The idea that a 'serious' play could have such an impact today seems basically 'zero' today. I've heard the arguments about ticket prices, competition from film, tv, but could the reason be that people no longer have a 'suspension of disbelief' but rather think that it's pretty dumb to watch real live people acting in front of you pretending they're saying and doing things that are just made up since it's so obvious that they are just 'acting.' And a related point, is there any playwright in the U.S. that can make a living just writing plays and not teach or write screenplays/teleplays as well.

What was the reason or reason's for theatre's downfall?concerts

If anything I think live theater is MORE believable for people because they don't have their house around them while they're watching -- they're fully immersed in the moment, along with hundreds of other people.

There are still a few serious plays that wow the critics, but the sheer cost of live theater vs the ease of DVD/TV means that many of them (Proof, Jersey Boys) end up getting made into movies. Even the goofy ones like The Producers end up as movies (where they often fail) even though they play to packed houses for years.

So it's not theater that's fallen, it's Serious theater. Maybe the world is in a phase where we need escape more than we need to be made thoughtful.

What was the reason or reason's for theatre's downfall?headache opera theater

Published books. Newspapers. Radio. Television. Movies. Internet. In that order.

Edit: Eh maybe movies a little before television. People went to the movie theater before they had household televisions.