What if the color line lasts until 1980? How does the boxing landscape change?

Absolutely correct. In the scenario you laid out, Cooper would be the Caucasian Champion, and nothing more. Same goes for Ali and his belt. Neither is a legit World Champion until they meet in the ring IMO.

Getting a tad off-topic here, but what opportunities would have been available for a guy like this back in the day..

https://boxrec.com/en/box-pro/40124

He did have a KO win over future title challenger Jack Roper. I'm assuming the color line would have kept him from a title shot as it did black fighters of the time. Would he have been given a shot at the Heavyweight Colored Championship if good enough? Haven't really heard much about American Indian boxers from that era...

 

Didn't the color line just apply to black folk? I don't think it stopped native americans. It didn't stop latinos (most of whom are about 50% native blood anyway).

 

Google AI says Latinos and Native Americans made up 0.7 and 0.35 percent of the US population in 1900. There just weren't very many.

Besides "Mexican" Pete Everett(who I'm guessing was a Mexican) did any Latino and/or Native American contend for a title during this period?

Latinos in Latin American countries could compete for the South American title which started up fairly early on around the same time as the IBU.

 

You are likely correct. Wasn't sure exactly where Native American people fit in the social hierarchy of those times. Seemed the Colored Championship applied only to Blacks. Hadn't heard of a Native American fighting for any belt in those days though.