or 

Here are three brief pros for each series.

Mario:

1. Is associated with Nintendo which has been making games for over 30 years.

2. Has a variety of high quality games not exclusive to platforming or consoles and maybe the reason why people buy Nintendo consoles in the first place.

3. Appeals to almost every demographic either as kiddy or a classic, retro gaming figure.

Pokemon:

1. Every main generation (excluding the third version and remakes) sell over 10 million over the past 15+ years

2. Has more merchandising power with amusement parks, movies, card games, and television shows.

3. Probably appeals more to children than Mario.

So which one do you think will live longer? I'm sure we'll see these two franchises being relevant in pop culture for a long time, but for how long?

Mario.

Neither will ever die

Both will continue on forever, so why even ask this question?

They probably will but it's more fun to choose one over the other. Maybe I should ask which one would be more relevant in the future?

Mario. Pokemon will end sometime

Mario.

Just because some day people can't remember 345 183 123 974 Pokémon and are tired of completing the Pokédex. And seriously there are more "enemys" for Pokémon which are more successful than products which competed with Mario. Mario is more powerful in that way and so he will have a longer life^^

personally I would have loved a "both" option lol I find many polls on this site never have it :/

I'd have to say Mario, come on! He's Nintendo's mascot for pete's sake! :)

Neither will die, but I'll say Mario.