Funny he mentioned Chris McCord as the originator of this technique with Liveview. The reality however predates that with Sync in Rails that you guessed it... was also Chris McCord's doing. Rails at the time didn't have the capacity to handle it so it was just a tech demo then and a big reason why Chris McCord moved to Phoenix. He was once a prolific Rails developer. That guy is helping the web move forward.

We were also doing this at Booking.com many years earlier, using morphdom and custom templating libraries. I think I wrote the first version in 2014-2015.