Every owner/GM needs to gamble for a team to succeed. Hindsight is always 20/20, but the truth is that every transaction is a risky move until proven worth. Freak accidents, team chemistry issues, etc are all factors you can’t measure before a trade/signing. Off the top of my head, rookie Kobe for Vlade was one of the biggest payoffs in NBA history (as for “riskiest” move, that is up for debate)
Mavs trading young star point guard Devin Harris for an aging Jason Kidd in a pretty desperate gamble for the title. It was a trade pretty roundly criticized at the time.
That Kidd/Dirk title team was great. Defeating the Heat must have been even sweeter.