When I was growing up, I certainly watched the NBC daytime line-up in the early 1970s. I was rooting for Doug and Julie every step of the way. Wanted Steve and Carolee to get together despite Dan Allison framing Steve for his murder. And I certainly was there watching Walter cry into the scarf every night while Lenore was in prison awaiting trial and Rachel doing her best to break up Steve and Alice.
That said, by the mid 1974 or so, I was busy with other things at school, in scouts, playing with friends, etc. I no longer made a bee-line to come home to watch soaps after school. I watched when I happened to be home, but not regularly.
But when in late 1974 when it was announced that Another World was expanding to 60 minutes, I was intrigued. I made a point of being home to watch that first hour-long episode on January 6, 1975. Was amazed they pulled it off. Then watched the next day to see if they could do it again. And watched the next episode, still stunned they were giving us an hour of show each day.
During this time, they moved Mac Cory front and center, playing up his relationship with Iris. Meanwhile, they also put Rachel in Mac's orbit, while moving her out of Steve Frame's orbit. This was quite curious. I wondered where they were going to go with this, figuring this was just a temporary thing.
Meanwhile, Iris was up to various antics including being engaged to Russ Matthews. Steve and Alice were seemingly happy. Pat and John Randolph seemed to be hitting a rough patch in their perfect marriage. This new whacky character of Clarice showed up with her, "Hiya, Iris." greeting. Needless to say I was hooked.
That's a long-winded way of saying, I was a lapsed viewer who tuned in to see what the hour-long show was like who then hung around for the compelling story being told.
I suspect that was the reason for the ratings rise in each show when it went to an hour -- lapsed viewers watching to see what a hour-long show would be like and then sticking around for good storytelling.