But in 2016, the notion of Durant spurning the Oklahoma City Thunder to join the Warriors also seemed ludicrous.
What would Durant's response be if LeBron James called him up to say, "Join me in Los Angeles with the Lakers?" Would it be an immediate "no," or would the All-Star forward have to consider the possibility?
When The Athletic's Anthony Slater asked in March whether he would "100 percent...be back with the Warriors next season," Durant replied affirmatively.
The team has since won its second straight championship against James and the Cleveland Cavaliers, and Durant won his second straight Finals Most Valuable Player.
Before the end of the month, Durant is likely to decline his $26.25 million player option for the 2018-19 season. He can then re-sign with the Warriors for up to four years and $158.4 million.
While that's still the most likely outcome (exact salary to be determined), Durant acknowledged to Sam Amick of USA Today that nothing is set in stone.
"This is the NBA, and anything can happen," Durant said. "And I know that anything can happen, (because) I've been a part of this league for so long now."
Over the past year, the Lakers positioned themselves to have enough cap room to sign two maximum-salaried players this summer, trading Timofey Mozgov, D'Angelo Russell, Jordan Clarkson and Larry Nance Jr.
If they waive and stretch out the remaining two years and $36.8 million of Luol Deng's contract (at $7.4 million over the next five seasons) and let go of all their free agents and nonguaranteed players, the Lakers would have $69.7 million in salary-cap space.
That would leave Los Angeles about $160,000 short of the room to give both James and Durant the max of $35.4 million (based on the $101 million projected salary cap).
If the two stars were willing, the Lakers would field a lineup with Lonzo Ball, Brandon Ingram, Kyle Kuzma, Josh Hart, the No. 25 pick in the draft, James and Durant.
In addition to the $4.4 million room exception, the Lakers would have only minimum salaries to fill out the remainder of the roster.
If the Lakers can find a taker for Deng—presumably with multiple draft considerations going out and without any salary back in return—they would gain an additional $8 million in space after signing both James and Durant.
While that wouldn't be enough for Los Angeles to retain the rights to pending restricted free agent Julius Randle, it might help the team keep a veteran like Brook Lopez or Kentavious Caldwell-Pope.
All the Lakers need is a "yes" from the two stars, and as Durant noted, "anything can happen."
If the Lakers were willing to part with young assets—perhaps two of Brandon Ingram, Lonzo Ball and Kyle Kuzma, with Deng either going to the Spurs or a third team—the math could work for a triumvirate of James, Durant and Leonard.
Los Angeles would go from a rebuilding team with promising prospects to a star-heavy contender.
The catch is convincing the Spurs to help the rival Lakers build a powerhouse. Oh, and getting Durant to leave the Warriors and James the Cavaliers for Los Angeles.
It's all a stretch...but wasn't that was the same argument against the unrealistic concept that Durant would join the Warriors in the first place?
Durant will likely return to Golden State. The Lakers, like the rest of the NBA, eagerly await James' next career decision. Leonard's fate remains a mystery.
Should James choose Los Angeles, the Lakers still would have enough spending power to sign Paul George as a fallback if/when this Durant hypothetical falls through.