I disagree with this. The reason Messi has been scoring more and more goals and the rest of Barcelona scoring less and less is because they are gearing up for Messi to be the main (almost sole) goalscorer. Compare nowadays to say 08-09 where Henry scored over 25 and Eto'o/Messi scored over 35.
Barcelona are absolutely raping La Liga right now, but guess what? Messi is the only player with more than 5 league goals, more than 5 times the amount of his nearest team mates. It has nothing to do with him lacking support, it is the polar opposite. Every player is clearly drilled to give the ball to Messi every time and watch him finish.
It is in fact the one of the two arguments against Messi being the best player of 2012 (certainly the best player of Sept 2011-Aug 2012). The fact he won nothing and the fact that he basically has 8 players whose sole purpose is to feed the machine.
This is why, despite its inherent flaws, statistics are very important in football whether we like it or not. If you're using the parts in bold as one of the main arguments as to why Ronaldo (I'm guessing) deserved to be the best player of 2012, then your argument is fundamentally flawed because the stats (All from whoscored.com) show that last season, Real Madrid were even more geared towards feeding the ball to Ronaldo in attacking areas than Messi. I think we can accept that a player that takes the most amount of shots in a team is the "go to" guy for goals in that team. Most moves end with that player taking the last touch of the ball before he shoots on or off target, this is more pronounced with a player like Ronaldo who is more of an "off the ball" player and likes to make deadly runs behind, rather than be on the ball a lot (like Messi or Rooney). Now, with all this in mind, I'm surprised you think it was Messi who was more dependent on the service of 8 players as you put it, because it certainly wasn't the case.
No of shots by Ronaldo 264, Goals 46
No of shots by the whole of the Real Madrid squad: 732, Goals 121
So, Ronaldo took 36% of Real Madrid shots, and scored 38% of their goals
No of shots taken by Messi 202, goals 50
No of shots by the whole Barcelona squad: 626, goals 114
Messi took 32% of Barcelona's shots, scored 44% of their goals
So what you're seeing there is that Messi was more efficient, took a smaller percentage of shots than Ronaldo relative to their teams (despite his bigger goal scoring burden with Villa out) and scored a higher percentage of goals than Ronaldo did, again relative to their teams.
The difference though is that the rest of the Madrid squad were more clinical than Barca's, hence why Madrid's other players scored more goals than their Barca counterparts.