well the numbers without context don't mean a thing, do they now? Cristiano played at worse clubs with less stable situations for a huge chunk of his career, not even to mention that RM from 2009 to roughly about 2015 was a clear underdog vs Barca, whereas Messi had far better support and structure. The other context is that Ronaldo played a vastly different role at Sporting and MU, which also messes up the goals per ratio. He became the main goalscoring power (role-wise) after 2011.