The Seattle Sounders and Toronto FC have been MLS members for less than half of the league’s 21-season existence, so why, as they prepare to clash for the championship Saturday on the icy shores of Lake Ontario, does it feel as though they’ve been waiting a half-century to raise the trophy?

Both arrived with overflowing expectations — the Sounders in 2009 with a fan base that would soon obliterate attendance records, Toronto as the Canadian big-city pioneer on a U.S. circuit.

With deep-pocketed backers, they’ve spent money like few others in MLS, embracing the designated player rule that allows teams to skirt the salary cap. Hefty contracts and recognizable names have raised promise but, amid annual shortfalls, also left deep disappointment.

For one organization, the short-but-long wait will end this weekend before a bundled and berserk MLS Cup audience at BMO Field.

“This is what all the fans in Toronto have been looking forward to for many, many years and have endured through those years,” Coach Greg Vanney said, lacking the perspective of, say, a Chicago Cubs fan. “They’re ready to explode and help push us over the finish line.”

Until last year, Toronto’s ninth in the league, the club had never qualified for the playoffs. Until this year, it had never had a winning record or playoff victory. In the first eight years, the club burned through eight coaches.

TFC, as the club is known throughout the city and league, seemed cursed by ownership, Maple Leaf Sports & Entertainment, proprietor of the Maple Leafs (no Stanley Cups since 1967) and Raptors (no NBA Finals in 21 seasons).

The Sounders’ existence has not been as glum: They’ve never finished with a losing record or missed the playoffs since joining MLS in 2009. They’re four-time winners of the U.S. Open Cup, an annual competition involving teams from all levels of soccer, and once finished with the most regular season points in MLS play, earning them the Supporters’ Shield.

Until this year, though, the Sounders’ 40,000-plus average crowds had not celebrated a trip to MLS Cup.

Seattle’s pro soccer history dates back more than 40 years, to the North American Soccer League followed by runs in rickety, low-flight alliances.

Reflecting on the Emerald City’s journey, Brian Schmetzer, the current coach, cited “the fans that started with us in ’74, through the ’80s, through the lean years and now. So it is a very, very big deal. As far as MLS standards are concerned, our fans have been waiting for eight long years for this moment.”

Seattle and Toronto have been among the most aggressive in signing marquee players.

Since last year, TFC has featured three of the most expensive players in league history: Italian forward Sebastian Giovinco ($7.1 million salary) and U.S. World Cup teammates Michael Bradley ($6.5 million) and Jozy Altidore ($4.8 million).

MLS’s average salary is $317,000; the median is $117,000.

Seattle lured U.S. star Clint Dempsey ($4.6 million) back from Europe and, over the years, has employed Sweden’s Freddie Ljungberg, Colombia’s Fredy Montero, Nigeria’s Obafemi Martins and Paraguay’s Nelson Valdez.

TFC began revving its engines in the summer, fueled by 2015 MLS MVP Giovinco, resurgent Altidore and captain Bradley, who Vanney said contributes with “blood, sweat and tears, and everything in between.”

The two-leg Eastern Conference finals against the Montreal Impact were an epic affair, with Toronto advancing, 7-5 on aggregate, after a 5-2 home victory in a second game that went to extra time.

Seattle, meanwhile, was hardly championship material in late July, stuck in a 6-12-2 ditch. Sigi Schmid, previously the only head coach in the club’s MLS era, was fired. Schmetzer, Schmid’s assistant and a fixture in Seattle-area soccer for decades, was promoted.

Uruguayan national team midfielder Nicolas Lodeiro ($1.7 million) arrived. Rookie of the year Jordan Morris excelled. The Sounders never looked back, despite the absence of Dempsey, sidelined since midseason with a heart condition. In the playoffs, they upset the Western Conference’s top seeds, FC Dallas and the Colorado Rapids.

In Toronto, the forecast calls for a kickoff temperature of 25 degrees, a nippy backdrop for a hot ticket. Remaining seats at the 36,000-capacity venue were gone in three minutes this week.

“I don’t think the weather will come into it at all,” Bradley said. “Actually, I think it’s going to be an amazing night to play. The atmosphere will be unbelievable. It’s about two teams who will go after the game in a big way.”

MLS Cup

Who: Toronto FC vs. Seattle Sounders.

Where: BMO Field in Toronto.

When: 8 p.m. ET Saturday.

TV: Fox national network, UniMas, Univision Deportes.