And Messi plays in Spain, where the gulf between the top teams and bottom teams is almost exactly the same. La Liga is like having 14 Wigan sides, 1 evertons 1 villa, 2 spurs and United and Chelsea.
Regardless of what level you play at, when a player plays at their level 'regardless of how poor or how good' they will remain generally in the same proximity to the player around them. You rarely see players score 50+ goals because they're often playing down a league so they get moved up. Neither Messi, Ronaldo or Larsson 'when he did it' could do that so what does that speak about their league? I doubt very much if either Messi or Ronaldo were playing in the EPL they would have more then 25-26 goals this season. Notice that when they play in the CL their goal count is generally similar 'perhaps a bit better' to the other top players.