I'd always wondered this, and didn't catch it when it was published.
https://www.thedreamshake.com/2015/2/12/8030535/why-charles-barkley-hates-the-rockets
https://www.chron.com/sports/rockets/article/Charles-Barkley-explains-distaste-for-Rockets-8323575.php
The only year that I was fat was my last year in Houston, because they had promised me $12 million," Barkley said. "When I showed up, the contract was only for $8 million. And I said, 'What happened to my other $4 million?' They said, 'Well we just decided to keep it.'
I was so pissed. What had happened was I took a paycut so we could sign Scottie Pippen ... So they said, 'We need you to take a paycut so we can sign Scottie.' I said, 'OK, I would love to play with Scottie.' They said, 'We'll give you $12 million next year.' So when I showed up the next year, they bring me a contract. I said, 'This looks like an 8.' They said, 'Yeah, we're going to give you $8 million.' I said, 'What about the other $4 million?' They're like, 'Well, we just changed our mind.' So I wasn't motivated.
This after playing an entire season for 1 million.
Makes sense.