Poor blue Mario; according to the NES boxart blue Mario was supposed to be just Mario (makes sense, blue overalls on a plumber), but the in game sprite won out:


There is hope for blue Mario to see the limelight, though. All Nintendo has to do is arbitrarily make him a playable character somewhere down the line (not too farfetched with gold-metal peach and queen honey existing), add a little personality, and let it snowball from there. It worked before

WAA

Blue Mario doesn't even have a page in the Mario wiki

Its a shame to, from the original Mario Bros games to now.
-Red Mario → Mario
-Green Mario → Luigi
-Yellow Mario → Wario
-Blue Mario → forgotten