It's hard to debate I mean, the OP never made quite clear on what terrain MArio could be "killed". In sales we can have a valid debate. Individually Mario games can be beaten by GTA, Call of duty or Pokemon just to name something random.
In platforming quality the debate get's tougher because hell, quality is subjective on it's own. I greatly prefer Mario over Ratchet and Clank in due to it's simple design yet depth of gameplay. I can imagine that someone else prefers constant action because they are ADD-sufferers with no taste (I kid, I kid)!
As a gaming-icon it is a non-issue. More people recognize Mario over Mickey Mouse. In the world he is the most well known videogame-character (though Pacman won in the US by a slim margin MArio was easly the champion in Europe and Japan.) Plus anything the other companies throw up as gaming-icons don't seem to stick. We may recognize the three green dots of light immidiatly as Sam Fisher, we see the value in Master Cheif and Snake but they aren't known to the general public as well as Mario. He will probably be recognized still even when videogaming dies...
The Doctor will see you now
Promoting Lesbianism --> 
