I agree. I think it's much more educational to watch two people pair program. Pairs have to explain their ideas and concerns to each other, so viewers are more likely to understand the problem, potential solutions, and general problem-solving approaches.
It can also help if the solo programmer is "rubber ducky" programming[1], but people typically assume more shared knowledge than actually exists. It takes another human to counteract this by asking for clarification.
Because I was just reading about this last night, it's the Curse of Knowledge[1]. Who knows what your audience is on a live stream? Viewers could range from "I'm also building a search engine and I'm curious about the techniques others use" to "I wonder what programming looks like". There could be gains for both audiences depending on how the process is presented.
Edit: I don't get how HN footnotes work... So I'll just pretend this is close enough.
It can also help if the solo programmer is "rubber ducky" programming[1], but people typically assume more shared knowledge than actually exists. It takes another human to counteract this by asking for clarification.
1. https://en.wikipedia.org/wiki/Rubber_duck_debugging