What happened to all the "9 to 5" jobs?

In old movies and sitcoms, most men are working like a factory worker, a police officer, a salesman, etc. They work 9-5, have weekends off, and out of all their jobs, maybe only 1 or 2 require continuing education. They're able to do their job and come home and forget about work, not ever having to worry about being called at night and tooled to be on call.<br><br>I realize that even in the old days too, there were doctors and nurses and police officers, too, that worked nights and got called in. But it seems like today, it's so common for a job to expect you to be on call 24/7 all week, and for you to be expected to be available 24/7, and for you to be expected to put in 80 hour weeks, with 60 hour weeks being the norm. It seems like there are way more jobs that expect 24/7 365 availability from all employees all the time too.<br><br>When did this change, and why?