R49, Not true. Several things severely wounded summer stock. Many of the same things that killed Catskill resorts and holiday camps. However, summer stock is not dead. Yes, you can go to the Ogunquit Playhouse and see Sally Struthers in something. Peterborough Players are still going, thought they no longer have stars.
One thing was air conditioners. It used to be that in a big city such as NYC, half the city would leave during the summer because of the heat and the smell. With air condition, people could stay in their air conditioned apt and go to an air conditioned movie theater... and even see a play in an air conditioned Broadway theater. Summer Stock tended to be near a place where people from the city "summered". When other options appeared, the summer stock theaters were hit hard.
Another is cheaper travel which allowed people to travel farther. Why go to the Catskills when you can go to Club Med? Note that Carnival Cruises started in the early 1970s. Again, there were al lot more options for potential audience members.
On the other side of the coin, there were changes for actors as well.
First, many of the old summer stock actors got started in stock or vaudeville. Barnstorming was in their blood. It also could be a huge ego boost to be the "big fish in a small pond".
As a part of this, actors saw personal appearances and interacting with the public as part of the job. It was like being a politician and shaking hands and kissing babies. Most actors would go to the opening of an envelope if it meant press.
Another contributor was changes in actor's contracts. The actors on most of the early TV shows were not paid high salaries, and even though residuals were negotiated in the early 1960s, many actors still did not receive them. TV actors actually need to work during the summer.
By the 1970s, TV actors increasingly did not have a stage background. When they were not filming TV, they were trying for a movie, not summer stock. Parallel to this, is the control of managers and agents. Obviously, a percentage of a film is better than a percentage of summer stock. There were/are "no summer stock" clauses in some contracts.
Lastly, the sexual revolution had a bit to do with it. In the old days, out of town was out of town. Summer stock was a place to have a summer fling away from prying eyes, the press, ...and often, one's spouse. When sex became out in the open, that dies down a bit, though The Williamstown Theater Festival was pretty much known as a sex club way into the 1990s.
