I make my own jeans & would love to have a overlock machine like he has in the video. I also use twill for the pockets. I usually make my jeans with zippers, but have done button fly.
I have a rivet setter, but mine is hand press. I just bought the rivet dies & not the rivet press/table, as I use my press for other leather setting dies. I can even make my own leather back patches.
I worked in a garment factory years ago. We made hunting clothing & heavy shirts. The factory closed & I could kick myself for not buying some of the machines back then. Sadly many of those good old machines were trashed & there is no company around to make them again. I read Levi Straus destroyed their original looms when they sold out to China. How sad those wonderful machines are gone forever.
I saw an embroidery machine, many years ago, sort of like the one he was using in the video, but it was an open arm. They used it at Disney World to write names on the Mickey Mouse hats.
As far as sewing "fast"....once you work in a garment factory you learn to sew very fast (almost as fast as the video). Even todays high speed domestic machines are no match for those old industrial factory machines. I sew flat out & to me todays domestic machines are slow.