Westbrook's contract is worse, and he's a worse fit, and they gave up a bunch of draft picks to make what could be a lateral move. Houston/Morey got fucking desperate.
I'd be surprised if this were the case. I imagine Presti probably wanted one prospect in lieu of a pick (since Miami doesn't have as many to offer I believe) but I would venture to guess the Miami deal fell through because they needed to involve a third team. It seems like OKC just wanted picks and salary dump.
It's not about them paying the tax. Paul George blindsided them with a trade demand and Westbrook didn't want to play for a lottery team so they had to trade him too.
They were paying an ungodly amount of money for a team getting bounced in the first round every season. If George wasn't traded somebody (probably Adams) was going to be.
Best offseason ever sets up the hopefully best season in a long time. Certainty unpredictable.