NFL wanted to mask confusion with other All-star football games
Plenty of other football was surrounding the NFL at the time and clouded their future. College football was something the country seemed to gravitate towards more during the earlier days of the professional league. Even the NFL had competitive leagues against them at the time that gave them a run for their money like the All-American Football Conference.
College football is still huge today, but the NFL still seems to be the more popular of the two brands as both games have evolved. Two All-Star events in football caused the NFL to struggle some in the early goings of the Pro Bowl and All-Star events. One thing that took away the hype of the NFL All-Star event was the Chicago College All-Star Game.
It was an event that had the NFL champions face off against some of the best college graduates across the country. It was an interesting idea that see the best team in the league face off against a team of college All-Stars trying to knock off the best in the NFL. It is something that many fans wonder if the best college team could beat the worst NFL team that year, but there was something like that before.
All-American Football Conference was its football league at one time and held its All-Star event called the "Shamrock Bowl". It was a one-time event in 1949 as the AAFC would join the NFL for the following season. A group of All-Stars would go up against the Cleveland Browns. It wasn't a long-lasting event, but it is an interesting footnote in NFL history.