I can understand it, but I think it's a shame. How many kids will never get the chance to win a grand final now (or even technically win a game), given a lot will drop out around U13s regardless. Most of us probably hold those memories forever, even from U7s or U8s. I'd prefer to see them tackle over-competitiveness in other ways.
All the research is good, but I don't think they consider the alternatives either. Kids who've never built up that mental resilience that (tackle) rugby league gives you... I'm sure there's plenty of kids whose parents stopped them playing footy who ended up on worse paths.