No one can deny that there are problems with the US Open Cup. Lack of proper promotion, poor attendance, lack of streaming options to name a few. But perhaps most telling is the indifference most teams put into the early rounds. In almost all cases, when a professional team enters the tourney, starters are rested, and bench players are brought in to get time, and to not expose key players to injuries.
The visuals this creates is problematic. If the coaches treat games like glorified scrimmages, and teams don't broadcast games, why should fans care? Aside from the novelty of regional rivalries, and low tier teams playing high tier teams, there is no really no incentive for teams to take it as an important game.