Keyword search and pagerank had working solutions decades ago.
Hotz was trying to make a car controller that had never been done before, by himself, and then he wanted to """improve""" search with no explanation of what that meant that I saw.
I think if he was tasked with taking twitter from no search to "has a search" he probably could have managed it. A team of five people definitely could have managed it.
I don't underestimate the effort, I claim that it's not strictly necessary to have more than a couple people working on it for a minimum viable product, and less for a beta.
It’s like me running a web crawler on my phone and saying I can replace Google.