Sony has none and I see it this way.
In nintendos case Mario is the mascot because he is a versitile character, not a one trick pony. Mario has been used in singel frame platformers, scrolling platformers, golf games, a tennis referee, a boxing referee, fotball games, baseball games, fighting games, puzzle games, racing games, party games etc. This helps building a strong brand around Mario (at a point in time Mario was more recognised than Mickey Mouse, I don’t know if this is true anymore tho). Most (almost all) people in the western world see Mario and know it’s that videogame character and in most cases specifically know it’s that Nintendo game character.
One of Segas failings is that they never made Sonic versitile, it was only a blue spikey character that could go fast. People that are not that invested into videogames will probably recognise it’s a videogame character, but probably won’t make the connection to Sega specifically. Sega should have stuck their guns to their original mascot Alex Kid but fudged it up in their 90ies effort to make a ”rad” mascot for all the ”mature” people playing Megadrive/Genesis. Sonics only saving grace is that he has been around since the 90ies.
Masterchief is just another generic GI Joe actionfigure for non gaming people. MCs brand recognition is close to 0 outside the gaming community.
All of above mentioned characters for team Sony are just one trick ponies and lack the versitility to create a mascot with a strong brand. R&C or Sackboy you probably would be able to make into mascots, buth the other ones nah.
You can always ask if sony needs a mascot and in short: probably not. But it wouldn’t hurt either.