Mcmahon should have thrown blank checks at Flair and Ted Turner in 1989 and acquired Flair. Hogan vs Flair was the dream match to end all dream matches for that entire decade, and its a travesty that the match did not occur during the tail end of that decade.
Millions of people wanted to see it, including people who didn't watch religiously. Even wrestling magazines used to have fantasy matches between the two on a regular basis several times a year. It would have made the Hogan/Andre spectacle look like a dark match.
Those mags(and fans) used to also dream of the top 3 champs of that era(Hogan.Flair, Martel) doing a battle to see who the real champ was. Strangely, Flair actually wrestled Martel in some obscure match in Japan that totally flew under the radar.
Crockett and/or Turner should have approached Mcmahon about a Hogan vs Flair match as a main event at a Crockett Cup and split the revenue. They were at war though so no chance of it happening obviously.
McMahon also totally missed the boat on Steamboat/Hogan. Steamboat was huge at the time. When he became NWA champion a year later, he actually challenged Hogan to a match(obviously bullshit just to draw attention), but it made fans realize how this dream match would never get to occur, and Vince could have made it happen a year earlier.