There was a great article about the unique appeal of the Open a few years ago - can't find a link to it now. Something about the passing of the seasons (how it is summer in NYC the first week, autumn the second week) lining up to the last major of the calendar season, and the progress of time (since often the retiring greats say farewell at the Open because it is the last of the great four tournaments each year).
It is a wonderful tournament, with glitz and charm (some unintentional) and a tremendous, forward-thinking history (equal-prize money since 1973, when it took the other three majors another 30-35 years to get their heads right). The Open has suffered, if it has suffered at all, and only on the ATP side, because (1) the greatest and most popular player has not won there in a decade, and (2) the greatest and most popular ATP rivalry potentially ever has never included a match at the Open.
Borg-Connors: 4 matches (two title fights) at the Open during their primes;
Borg-McEnroe: 2 matches (both title fights) during their primes;
Connors-Mac: 4 matches (including de facto title fight in '84 on the famous Super Saturday) during their primes;
Connors-Lendl: 4 matches (two title fights) across the 80s;
Lendl-Mac: 5 matches (two title fights) across the 80s;
Lendl-Wilander: back to back title fights there, 1987-88;
Agassi-Sampras: 4 matches (three title fights) between 1990 and 2002;
Roddick-Fed, Hewitt-Fed each had a title fight there when their rivalries were still meaningful.
And of course:
Federer-Nadal: 0 matches there
As a consolation prize, the Djokovic-Nadal trilogy at the top of this decade was fantastic; Murray's 2012 triumph was really compelling and has been somewhat unfairly overshadowed by the Wimbledon title the following season; Del Potro's 2009 win was magical and tragic; and, further to that article's point I mentioned above, the Open continues to consistently introduce and say farewell to compelling figures of the sport in terms of early- and late-career great runs at a major:
Ashe 1968
Tracy Austin and Mac, kid titlists, 1979
Lendl makes a teenaged run to the quarters in 1980
Evert's farewell trip to the quarters, 1989
Sampras bookend titles as a teenager and thirtysomething, 1990 and 2002
Sabatini breaking through in 1990
Connors, 1991 semis, the lion in winter
Venus 1997, Serena 1999, the dawn of a new era at the close of a century
Agassi farewell runs in 2005/06
Clijsters breaking through in 2005
Safin drawing and quartering Sampras in 2000, Hewitt 2001, Roddick 2003 (and his emotional 2012 farewell and visor-clad teenaged run to the quarters in '01)
Kid finalists/titlists Djokovic 2007, Murray 2008, Del Potro and Woz 2009
Murray breaking through in 2012
Kei/Cilic offering a glimpse of what the Lost Generation may have been, 2014
Flavia 2015 (and Vinci felling the queen a round earlier)
Sloane breaking through, Shapo making the second week, 2017
Man, what a great tournament.