Sales and everything else.
Google Pokémon: About 7,330,000 results
Any metric you use GTA will be more popular than Pokémon.
Mario >>>>>>>>>>>>>>>>>>>>>>>>>>>> Both btw.
UsingGoogle Searches? :P
Well here's my metric. Pokemon Centers/Stores > Not 1 GTA store
But seriously, i think this one is hard to put, i see why people think GTA is more popular but still....
Let me say this Which is more popular? LoZ or Uncharted... First of all Uncharted beats Zelda last gen in sales (Excluding HH/spin offs), by a good margin right? Does that mean its more popular? (we can go on but just pointing that out).
Then we have a game as SSB vs Halo. Both are Nintendo's (well probably 3rd/4th) and MS biggest franchises respectively. SSBB barely outsold H3, but MS also had H4/Reach released last gen, and now currently SSB 3DS+SSBU vs Halo:MCC. Which is more popular? Saleswise Halo (so far last gen+before that), but how many people play per copy?
Thats the question you need to ask yourself^ SSBM a game that sold 7mil copies, probably has over 30mil people who played the game (not counting just played once or twice). I mean SSB+MK are the kings of Local Multiplayer, especially SSB