When Did 9 to 5 Become 8 to 6/10 to 7?

Maybe in 1980, when 9 to 5 first came out, the office schedule was still firmly in place. But now, it seems there is utter lawlessness with regard to how long a person has to stay at work. Back in the day, the lunch break was like a magical perk that was a part of your workday, but now, it’s completely separate–a forced chore.
The “meal break” one is legally required to take really adds some unnecessary time to your workday. Personally, I would prefer skipping a lunch break altogether if it meant leaving to go home earlier. But alas, a full eight hours is really nine hours when you tack on a mandated lunch hour, making it difficult to tell which conditions would be more gulag-like: working non-stop to bounce before 5 or being conned into staying longer for the supposed benefits of pausing for food/respite.