This video doesn't really mention the important competitive reasons the legacy carriers prefer the hub and spoke model — it essentially kills competition in large parts of the country.
If you are based in DFW, you're basically forced to be loyal to AA because it's the only carrier that serves a large number of destinations from DFW. If you live in IAH, you're basically forced to be loyal to UA. And so on.
That means the legacy carriers can charge much higher prices because on a lot of routes there is no competition for direct flights — only much longer indirect flights from other carriers.