Not making the all star team does not mean Brown and Tatum "missed the mark". Both could progress right on schedule and miss the all star team, even if they were clearly worthy of it.
Who knows what the Memphis pick will become, and Tatum alone may turn out to be worth more than Towns. Hayward will be a FA a year from now, and Kemba + Towns doesn't look like a title contender to me. Further, I don't trust Towns work ethic. His L-T contract is a double edged sword. Yes, he's locked into it for several years, but so are you, and many a high paid athlete has turned into a potato with all that guaranteed $$.
And on top of all that, winning a title with your own players is vastly more satisfying than bringing in mercenaries for a few years. A title with Smart, Tatum, Brown, the kids we just brought in would mean far more to me than cobbling together a few contracts for a 2 year run then starting over again.
Unless it's involving bringing in one of the top half dozen or so players in the league (i.e., not Towns), no way I'm trading Tatum. I believe he's going to be a superstar.