Houses of Hermes: True Lineages implies that only works from Bonisagus magi are collated into the folio, but given that any magus can perform Experimentation and Original Research is there any reason why works from other houses might not be considered?
For a depressingly pragmatic reason: no one else cares and magi are incredibly selfish.
Bonisagus Bonisagii tend to be the ones who get credit and status from sharing their research. Therefore, there's a self-perpetuating cycle where the participants in the exercise are those who derive value from the exercise.
While normal magi are nominally willing to score points with the Bonsiagii by submitting spells and other low-impact researches, original research takes years, and more importantly, non-trivial amounts of warping to complete. The mystery cults have a tradition of secret and inscrutable mysteries, which this sharing of the original research flatly contravenes. Societies tend to not perform this, or share (if at all) among their sodales for reasons of personal gain.
Therefore, other houses engage in original research less frequently, have traditions less inclined to value sharing, and in general, like getting the benefits of other people sharing.