No..
not really any secret strategy. Pop stayed big the entire game against small lineups that killed the Spurs. It was clear what Pop's plan was, he never adjusted by introducing variables, playing small, playing Bertans, Simmons, etc. Pop had a plan to see if his bigs and crew could execute and they didn't. They made a lot of mistakes on defense and offensively wasted possessions and didn't get good enough shots or spread the ball around enough with passing. The lineups he put out there were his best lineups if he stays big. The Spurs chose to stay big in FA choices this past summer, spending almost nothing at PG and wings depth so even a small unit may not be able to perform better, but Pop never tested it.
I just think it was more valuable for Pop to get enough footage/film and experience than to cut things short, introduce variables like Bertans, Juice, etc. It's late in the season to be tinkering and he's still tinkering. It's a sign of this team not having the continuity of times past.
He let it play out so he could learn about his team, the players etc. So yes it's an optimistic take, but not one that involves witholding some secret hand, just Pop letting his idea play out and then adjusting (in the future)