The Women's United Soccer Association (WUSA), the first-ever professional women's soccer league in the world, folded after its third season. Its successor, Women's Professional Soccer (WPS), folded after its third season. The latest iteration of stateside female pro soccer, the National Women's Soccer League, enters its third season on Friday.

Here's some more anecdotal evidence that might induce worry, if presented entirely free of context: The WUSA and WPS collapsed after their 2003 and 2011 seasons, respectively. Those were both Women's World Cup years. 2015 is also a Women's World Cup year.

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But the NWSL isn't anything like its predecessors. Following the wild success of the 1999 Women's World Cup here in the United States, the WUSA launched with much fanfare and bloated budgets. From the first day until the last, it hemorrhaged money. The WPS was more modest in its business model but still paid out fairly sizable salaries to star players; that didn't work either.

So the NWSL is, by comparison and any other measure, a fairly bare bones operation. For an upstart women's soccer league, this is simply a market-mandated necessity.

Cognizant of the need to have a healthy professional women's league in North America – as competitors spring up around the world and help develop better national teams – the soccer federations of the U.S., Canada and Mexico agreed to cover full-time salaries for their national teamers active in the NWSL. By essentially writing off the big payroll hits for its most famous players – probably its largest cost by far – the league's chances of survival instantly multiplied.

"The most certain way that we avoid that fate [of preceding leagues] is the relationship and the commitment from our federation partners," said new commissioner Jeff Plush, a long-time sports and soccer executive who was installed in January. "It completely changes the dynamic of what the last two leagues had going against them."

Like any startup business, it's difficult to get a sense of viability at the dawn of its third year. When there are issues, are they growing pains or early signs that the product simply isn't in demand?

View photos Abby Wambach opted to sit out the NWSL season to get ready for the World Cup. (AP Photo) More

The NWSL has no shortage of challenges. Almost all of its nine teams play in tiny venues to anemic crowds. While the Portland Thorns have gotten an average of 13,300 people through their gates in each of their first two seasons, most clubs are closer to the Sky Blue FC's figure of 1,600 in Piscataway, N.J. Television deals have been meager – the little-watched Fox Sports 2 showed six regular season games and all three playoff games in 2013; and in 2014, ESPN2 aired three regular season games and the three-game playoffs, and online-only ESPN3 put on three more games. Lacking national or even local television exposure, clubs mostly broadcast their own games through YouTube.

Salaries, meanwhile, are microscopic. The entry-level class of players makes $6,000 per season. And players who aren't on the national team payrolls top out at $30,000, making it hard for them to stay in the league once they pass their mid-20s and expect a little more comfort in life.

There are few foreign superstars coming over anymore, the way they did in the WUSA and WPS. In fact, plenty of NWSL players go abroad in the offseason, ostensibly to stay in playing shape, but probably just as much to draw a few more paychecks. U.S. star Abby Wambach decided to skip the club season altogether to spare her battered body for the World Cup.

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