On lichess and other forums, players tend to play opponents with similar ratings. Since Magnus Carlsen's opponents don't leave things en prise as often as the average player, Carlsen may not make that many captures per move, but I bet he captures more often than his opponents.

If I played against a master, he or she would capture a lot of pieces, and I would only capture a few. Can it be concluded that I have a higher Elo rating than him/her?

That's the thing: a master would beat you without taking a lot of your pieces. They'll play for position, rather than material advantage. Your pieces will be less of a threat, and won't be guarding the squares they need to guard. Taking material would just slow them down.

They might even just let you take pieces, since you don't know what pieces are involved in the attack and which aren't. There's even a name for it: "pawn munching". It's not a compliment.