So for the foursomes players, this format was a slap in the face, but on the other hand, it may even be a victory for tennis as a whole. The mixed doubles filled the Arthur Ashe Arena for two days in a row and was visible to everyone on prime time television. Maybe next year, however, they will dare to include a few more foursomes players.
Yes, the stadium was filled. The tickets were also affordable and much cheaper than in the main two weeks. As I've said on another thread, ground tickets during the main two weeks are between $150-$400. And Arthur Ashe even more. During fan week (which is essentially free) I heard the mixed dubs tickets were around $50 (that's what a good friend paid). It isn't the entire reason, but a contributing factor.