My guess is those that use Nintendo systems for their games, Nintendo uses their characters as homage to them:

Capcom has a lot of games on Nintendo consoles, like Monster Hunter and Phoenix Wright, which is why Mega Man and Ryu are there.

A lot of Namco games are in abundance with Nintendo consoles, which is why we have Pacman.

And even Square-Enix has some good games with Nintendo, like Bravely Default/Second, re-releases of Final Fantasy III and IV and three Kingdom Hearts games, and with the upcoming release of FFVII HD, the stars are perfectly aligned for Cloud to make his entrance.