The Montreal Canadiens have been two different teams this season - with Andrei Markov and without:
While Markov is a good player, he is not this good. If we attribute all of the improvement to Markov, that would make him worth more than 11 wins, which has a value in excess of $25M. It's not clear that any NHL player has even been worth that much, even in his best season - more reasonable estimates put Markov at 3-4 wins over an entire season, or 1.5-2 in half of this season.
Montreal has been significantly outshot this season, and it hasn't mattered whether Markov has been in the lineup or not. What has changed with Markov is the team's shooting percentage and save percentage:
The very best players do have a small impact on shooting percentage and save percentage, but it's only 10-30% of what we see here. A PDO (shot% + save%) of 1025 is impossibly high and only the Oilers, Islanders and Canadiens dynasties of the late 1970s and early 1980s have had this level of skill. Modern teams do not exhibit this level of ability.
Where we do see the benefit of having Markov in the lineup is in the total number of power-play and shorthanded opportunities per game - PPs go up, PKs go down:
I'm willing to believe Markov is responsible for a big chunk of that change. The Canadiens have also had a much higher power-play efficiency since he came back, to the point of having by far the best numbers in the league. As I mentioned with respect to shooting percentage, only a very small part of that is Markov; the rest is luck and his teammates playing to their real level of ability.
Bottom line: Montreal played much, much worse than they really were when Markov was out of the lineup. Now that he's back, they're playing slightly better than they really are. The contrast is huge, but only a small part of it is due to Markov himself.