I think it's alot easier for teachers to travel than all of the students. Budo practice usually happened around a local teacher and dojo in days gone by. Travel was difficult even though distances weren't as great as in the US for example.
Budo practice around the world now must find a way for students to get exposed as often as possible to the most senior teachers possible.
Seminars are a good way to do this and support teachers/organizations as well. A wide variety of teachers' teaching styles make it possible for students to find connections that are meaningful for them.