Messi was the Golden Ball (player of the tournament ) winner in the 2014 edition of the WC. If he was a dud, so was Sachin in 2003.
So was Luca Modric this time, yet how many players remember matches of pure brilliance from Modric in this World Cup or Messi in that World Cup? Kohli also played pretty well in this World Cup, he consistently scored half centuries, yet he did not dominate, played second fiddle. All matches were carried through by Rohit Sharma, K.L Rahul or Dhawan, he just played second fiddle. That is why he did not score the highest runs in any match (except may be against West Indies, who unfortunately are minnows these days, even Bangladesh beats them comfortably), he did not play any dominating innings in the tournament.
Contrast that to Sachin in 2003 or Maradona in in 1986. Millions of people still get goosebumps when they remember Sachin's 98 against Pakistan, 97 against Sri Lanka, 50 against England, 83 in quarter final. He was the highest scorer in that tournament, highest scorer for India in most matches, dominant enough to steal the limelight in most (or at least many) matches. Just like Maradona did in in 1986, winning the semifinal single handedly in one of the greatest showdowns of all time, did phenomenal dribbling and passing throughout the tournament, to the point that he was singlehandedly man-marked, contributed to goals in the final by passing the ball perfectly. Just like Zidane did in 1998, Ronaldo in 2002.
Winning the golden ball is not index of dominance and phenomenal play in a World Cup. You have to give impactful performances taht won you the cup, worth remembering for a lifetime, Sachin did, Maradona, did, Zidane did, Ronaldo did, Wasim Akram did, Yuvraj Singh did.
Kohli or Messi hasn't. Yet. Not one of the "World Cup Xi" by the experts, or public polls fro Fantasy XI, has Kohli. Sachin was there in every World Cup XI team by experts in 2003, generally the first choice.