Apart from it not really being in anyone's financial interest - not content providers, copyright holders or advertisers, it would be viewed as a security risk if anyone could easily do that - e.g: https://www.theverge.com/interface/2019/4/4/18294951/austral...
The idea of using multicast in this way also ignores some of the actual good features of HLS, in particular the ability to adapt content to a specific user's device and Internet connection.
The idea of using multicast in this way also ignores some of the actual good features of HLS, in particular the ability to adapt content to a specific user's device and Internet connection.