ngodrup wrote: Scholars have very little access to Bonpos living inside Tibet.
Not to contradict you out of reason, but this is really not true. There has been a 10+years gigantic survey of Bon made by a group of Japanese scholars including a lot of western scholars (under the direction of Y. Nagano and SG. Karmay) covering all aspects of Bon in Tibet in particular. There were also a few things done within this project in India and Nepal but by far the bulk of the work (history, language, monasteries, etc.) was done in Tibet itself. There are several scholars (including Marc Desjardins) working directly with Bonpos in Tibet. JLA also did some work directly with Bonpos from Tibet. In fact, we have a very good picture of what Bon is, much better than 10 years ago. Moreover, this access to Bonpos in Tibet is made easier since Bon is one of the most active religious entities in Tibet nowadays. This is particularly true in Eastern Tibet.