Why cant the uniforms of featured colleges be used in DD?

This isn’t a big issue, and I understand people like myself will still make college teams in the jersey editor, but now that they have the select amount of colleges in RTTS for two years now, why can’t those colleges jerseys be unlocked in DD? It’s even weirder considering you can use the team’s official names for your team audio. Is there any actual reason they can’t put their uniforms in Diamond Dynasty?