I see a possible problem with this theory: in few words, according to the authors the French and Scots did not adopt the longbow for fear of rebellion. Still the nobles participated to the very battles that saw them being defeated by the English and their longbow. If the longbow was cheap and relatively easy to adopt, a noble aspiring to the crown would have been able to develop the technology independently from the (unstable) central government and have an even easier road to glory against their own technologically inferior king.<p>I admittedly did not read carefully the whole paper, but this possibility does not seem to be addressed.