Could Powell have been worth more a week later at the deadline? Possibly. Could he have been worth at the least what LaVert and others were at the deadline when traded for an actual first round pick? Possibly. If we had then flipped such first round pick from a Norm trade for Grant could the Blazers have drafted Duren? Perhaps. If Cronin never found a deadline deal for Powell could he have been worth much more this summer? Possibly.
Cronin stated he worked to get players to their preferred destinations. He also said he felt pressured to do the Clippers trade to duck the tax and negotiate a CJ deal, a clear sign of an inexperienced negotiator. You don't know for certain the league's value of Norman Powell was low and would remain so any more than others suspect it was higher. GM's don't always make moves for the best long term value or the best long term maximum return. We know Norm was traded for a player on a rookie contract in Gary Trent Jr. A GM job is to maximize the value of players they send out and acquire players for the least assets or smallest team friendly contract.
Cronin failed to get any meaningful asset for Norm or Roco. The Blazers are a long way from having contending talent; they can't give up multiple starting level players for meaningless returns and build a winning team. It's better to hold an asset for a possible valuable return at a later date, then to dump it immediately for irrelevancy.