Paradoxically, the years that preceded the 1994 World Cup in the United States were some of the hosts country's least stable. It had been years since the USA didn't have a top division, the ASL folded in 1983, the NASL folded in 1985 and even the Major Indoor Soccer League folded in 1992. Even though the MLS was founded in 1993, the inaugural season only took place in 1996.
With this context, the US Soccer Federation did something extremely rare in the history of the sport. Without a proper national league the only option American players had was to play aboard but not all were able to do so. To solve this problem, instead of calling up players from their clubs, the federation signed players directly. Important names like Brad Friedel, Cobi Jones, Alexis Lalas, Claudio Reyna and captain Tony Meola, all were club-less, and signed only to the USMNT.
Since the players didn't have clubs to play for the federation had to find a way to fill up their calendar to prepare the player for the 1994 World Cup, after all, the 1990 World Cup was a disaster. Aside from scheduling a friendly match whenever possible, the USMNT would enter a 4 year sequence for official and unofficial tournaments to try to give their players the playing time they needed.
In chronological order these tournaments were: CONCACAF North American Nations Cup, CONCACAF Gold Cup, King Fahd Cup, US Cup, Kirin Cup, CONMEBOL Copa America, Lunar New Year Cup and Joe Robbie Cup. A couple of things worth noting is that the King Fahd Cup was actually the predecessor of the extinct FIFA Confederation Cup, and the US Cup was a cup organized by the USSF and was played annually from 1992 to 2000 except for World Cup years.
Given the circumstances of their preparation Team USA didn't do bad at all in 1994, they made it passed the group stage and got knocked out by Brazil who would go on to be world champion. Just two years later the MLS would become home to US players domestically, and the top athletes would find room in Europe's best clubs. It's important to have this perspective in order to appreciate how far the sport has come in such a short amount of time in the USA.