Uh, you do know that Carlsen has made some contributions to the London System right? Jobava popularized the Jobava London System (although one could argue this isn't really a London at all). Niemann plays the London (aggressively to be fair though) and lots of other top players use this opening.
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I do know. But neither Carlsen or Niemann are die hard London players and the London isn't an integral part of their core repertoire.

You shouldn't be disappointed. There are some top players that play the London every now and then. The London is not really a Bad opening. Just like the French Defense, there are criticism about black's light square bishop that is sometimes not really active in the game, yet some you still see some GMs play the French Defense.
I can't believe Fabiano came out as a die hard London System player. I am very disappointed.