Yes, Zelda should be more popular than Mario, since I think that the Zelda games are of higher quality than Mario games. Along with this, I wish for Link to be the Nintendo mascot instead of Mario. However, I know that this will most likely never happen, since there are several more Mario games out there than Zelda games, and by this point in video gaming history, Mario's worldwide fame has gone way too far that there is no chance that his series would not be more popular than the Zelda series.
However, this does not upset me, since I love Mario games as well, and I think they should be properly credited. Even though I believe Zelda should be more popular than Mario, Mario being more popular than Zelda does not upset me and will not upset me if it is kept like this forever.