Yeah that seems like a likely explanation, but still if there was a push to start recording and publishing courses (beyond the level of individual professors who sometimes put their courses online) they must've had dedicated staff at some point.
It's hard to keep staff once a project is "done". Even if they wanted to stay, departments have budgets and its hard to justify a salary for someone to maintain free access to lectures. Based in the general lack of uniformity on university websites, I wouldn't be shocked if at least some of the people cobbling them together were students working part time who eventually just move on to the next stage of their careers.