You are correct. When we first talked about Lists, I was literally thinking of my mom, cliche as that is. She had a Twitter account, but at the time probably only followed my sister and I. I thought, if I sat down with her, I’m sure I could build her a timeline she’d like. Wait a minute: What if I could build her a timeline she’d like without sitting down with her? (Not that I didn’t want to sit down with my mom, but she lives in Iowa.)
So making it easier for other people was literally the first use case we had in mind, not the power-user use case. Another use case for everyone was being able to tune into an interest or event with one click and turn it off as easily. That’s kinda what lists are today, but the idea was not for them to be this secondary (or worse) surface.
The original idea was that you could toggle them on and off in your main timeline. We actually had this built at one time, though as a prototype so we couldn’t quite ship it. It seemed great, but other priorities prevailed.