The decisions from the Boston Celtics and Philadelphia 76ers not to pursue a trade for Kawhi Leonard during the 2018 offseason appear to be at least somewhat misguided with the advantage of hindsight as he led the Toronto Raptors to a ring. The Celtics and 76ers each presumably had enough available assets to give the San Antonio Spurs a better package than the Raptors while leaving enough talent to surround Leonard to compete for a title.
Sources with both the Celtics and 76ers tell ESPN's Kevin Arnovitz that the informed believe that Leonard had every intention of signing in Los Angeles in 2019 was the determining factor in not trading for him.
The Celtics were believed to also be saving their assets for an Anthony Davis trade that ultimately never materialized for them following the expected departure of Kyrie Irving.
The Spurs, meanwhile, wouldn't discuss a trade with the 76ers that didn't include either Joel Embiid or Ben Simmons.