I don't think his attitude has shifted. He's always wanted to win a championship
and 3 years ago he went over Olshey's head and talked to PA directly about the direction of the team. After that conversation the Blazers won 53 games and made it to the WCF where they got swept. Olshey's response to that was to essentially exchange Aminu-Curry-Harkless-Kanter-Turner-Meyers-Layman for Whiteside-Bazemore-Tolliver-Hezonja-Skal...and a losing season
then, this year toward the end of the season, Dame talked about how he had a good feeling about the team and thought they'd be strong in the playoffs...then they lost to an injured Denver team
then, Olshey fired Stotts and said the roster wasn't the problem...then he got rid of half of the roster
I think Dame has been pressuring Olshey and ownership for a lot longer than this summer. I'm betting he's been doing it quietly behind closed doors. At this point, I'd imagine he has little confidence in either management or ownership, and rightly, sees no reason to back off and relieve pressure on management by making a long term commitment to the team after 9 years of loyalty