Well, there are precedents. In 1986 a young pair won worlds their first time out, and for a couple of years people debated whether they 'should' or 'were ready' to win the Olympics or even worlds. Gordeeva and Grinkov won as everyone knows. And that win didn't prevent their desire to develop artistically; and they succeeded, with detours and challenges along the way.Yes, the judges have chosen their favorites but B/K and T/M clearly do not agree with it and they are close enough so they keep pushing. (And I'm actually praying for M/G not to win that Olympic gold because they are so young and with huge space where to develop artistically. This may not happen though if they win all imaginable medals so early in their career.)
Also, Mishina/Galliamov have stated that it's their intention to continue developing their skating artistically and stylistically as well as technically. I believe them. Their candor and sensitivity to each other and others are part of their charm.