I may be wrong, but that clip looked awfully like a section of the video of a number of students of quite well known masters demonstrating in Taiwan. It looks like part of a two person choreographed chin-na form.
I think that students of teachers who fought/knew how to fight had a much better chance of passing on their art as a fighting art, but many teachers did not pass all they knew on to the next generation for a variety of reasons. Sometimes it’s age, sometimes ability, bad luck – who knows? Sometimes, with the best will in the world, their students could not grasp what they were being taught. Aspects of the arts are certainly being lost, but they are broadening, too.
Modern technology is a brilliant resource for tracking down people with the skills that you want to develop or for filling out parts of the art that you were not taught. My early beginnings were basic longfist, but it is only recently that I have seen workable applications of some of the moves.
Of course, there are skills that are not ‘available’ to view online and those would require a healthy dose of luck to find.
Graculus
https://Ichijoji.blogspot.com