On some level, who cares if I can't pay some node I was never going to pay anyways? Maybe the amateur nodes aren't actually getting worse at payment reliability? Perhaps they are just optimized for paying hub nodes rather than paying one another.
Super important point. I am sure when Rene publishes the work he would have it as a limitation/caveat of the research. What can be interpreted, what can't be interpreted. IMO, the purpose of work like this is to invent and share methodology.