The flaw in the logic is that it is only in hindsight that we know that Jordan would be "best ever" and Drexler would "only" be a "top 50 of all time." And we did not know that Bowie was going to be a "pretty decent Center" and not an "elite NBA Center" The pick was only criticized years later in hindsight. The Blazers likely had ranked Bowie and Jordan about the same, in which case they pick for need. In hindsight, they were wrong, but given what they knew at the time, it was not a stupid pick. Remember this was Dr. Jack Ramsay-coached team, who certainly had a major say in the pick -- hardly a basketball mental midget. This is especially true because a really important part of what made Jordan "great" to "best" was mental. His drive, work ethic and mentality were amazing (see Kobe, Stockton, very few others.). Hard to forecast the mental part of the game.
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And the Gobert analogy seems really off the mark. Which teams do you believe passed on Gobert because they already had a dominant rim protector? Seems more likely that it was because they did not believe he was going to be a dominant rim protector and had high bust potential. Interesting, what differentiates Gobert is the mental game that complements his physical tools. Put Ostertag's brain on Gobert's body, you get something pretty close to Ostertag.