The traveling circus
The NFL used to always host the draft at Radio City Music Hall in New York City. One year, the venue wasn’t available so they moved the draft and the rest is history. Now the draft is a big-time even that travels throughout the country. Teams and cities vie for the right to host players simply walking across the stage.
At least with the combine we can see players do something athletic. The NFL is consistently searching for ways to increase revenue. There’s a pretty easy answer to do so: move the combine around the country and make it a big event.