I work in game dev and there is a similar "industry" of people who stream and create video content of games. Similar to celebrities, people who come from pro-gaming have a much easier time establishing a fan base. Many people try to get into streaming with no relevant background and some totally flop but others do manage to build significant audiences over time. Some people will launch a stream of themselves playing a game and hardly say anything - who is going to stick around to watch that? Other people have regular streaming / content posting schedules, which helps to keep people coming back. They have personality, often some kind of twist on what they do, and they engage a bit with the audience / give them some bit of window into their life. I think the personal connection is a lot of what keeps people coming back. Regularly producing new content on a schedule and keeping fans engage obviously takes dedication and time. That isn't to say that you can't do "well enough" with a moderate effort. Like you have game streamers with an audience of millions at the top and they make millions per year but you also have smaller streamers with only 5-10k followers and it's not a career but they make some decent money and its sort of like a hobby that pays you back.
A lot of it depends on how much you want to put into it. I guess what I'd say to your wife, which may be comforting, is if she doesn't end up with many followers, its probably not about her, it's probably just about the amount of effort put into PR and content production. There's a lot of people out there with good looking bodies but a lot of it is about dedication and showing some personality that people can connect with.
