World Chess Championship will move on to rapid games
nytimes.com
nytimes.com
While people keep looking at FIDE's ranking list (https://ratings.fide.com/top.phtml?list=men_rapid), most seem to be ignoring the fact that Magnus Carlsen's 2880 rapid rating has not been updated since January. There's simply no guarantee that he's still at a 2880 level. This appears to be quite a quirk with FIDE's rating system - it's certainly not how professional tennis (see: Serena Williams during maternity leave) or cricket rankings work (see: Steve Smith's ranking after starting his 1-year ban).
Meanwhile, in the 2017 World Rapid Championship, Carlsen did not finish 1st despite having an Elo above 2900. In fact, he came a "lowly" 5th, and finished behind Bu who was a 254 points behind (seeded 68, or ranked roughly 88). Meanwhile, Anand, seeded 12th but ranked around 17 or 150 Elo behind, won the title.
Right now, while Caruana is ranked 10th, he is still higher than many players who have in the past been considered stronger than him at rapid - in tennis terms, the ranking difference is nothing (for the record, he's only 91 Elo behind, if we can trust that system). The pecking order appears perennially turbulent.
Lastly, Caruana actually finished 2nd in the 2014 World Rapid Championship - https://en.wikipedia.org/wiki/World_Rapid_Chess_Championship... - it's definitely note far-fetched to consider the question that he could well win the rapid tiebreaks, and also achieve 1st at the upcoming World Rapid Chess Championship (provided it's not held in Saudi Arabia) next.
Some more archived tables for dissemination:
https://web.archive.org/web/20170909194137/https://ratings.f...
https://web.archive.org/web/20171115220847/https://ratings.f...