How come there aren't enough villains in the Street Fighter series?

My guess is there are too much friendly rivalries, so that there are some good vs. evil and even evil vs. evil opposites like Chun Li has Juri, Guile has M. Bison, Dudley has Balrog, Sagat has Adon, Gouken has Akuma, Charlie temporarily rivals with Rolento, Guy has Sodom, Alex has Hugo, Necro has Twelve and Gill has Urien. I think Birdie would make an excellent rivalry with Eagle and Ryu, Ken Masters, Gen, Blanka, Zangief, E. Honda, Dhalsim, Vega, T. Hawk, Cammy, Fei Long, Dee Jay, Rose, Dan, Sakura, R. Mika, Cody, Karin, Juli, Juni, Maki, Ingrid, Hokuto, Doctrine Dark, Pullum Purna, Cracker Jack, Skullomania, Blair Dame, Allen Snider, Kairi, Darun Mister, Garuda, Sharon, Hayate, Shadowgeist, Nanase, Vulcano Rosso, Area, Ace, Cycloid Beta, Cycloid Gamma, Yun & Yang, Ibuki, Oro, Elena, Sean, Remy, Makuto, Q, Crimson Viper, Abel, El Fuerte, Rufus, Seth, and Hakan need to have villainous rivals for real.