Ronaldo has gone from scoring 48 and 46 league goals in a season 5-8 years ago... to 31 league goals last season.
Messi has gone from scoring 50, 46 and 43 league goals in a season 5-8 years ago... to 25 league goals last season.
Sure that is still superb by both of them, but it is a significant slowing down in their goal-scoring.