Ripple 1: More Spurs Favorites Traded
As noted above, a Spurs' trade on Simmons would be all-in. However, the trade itself would just be the tipping point. In his first several seasons, Simmons has shown an inability to play with non-spacers. He needs to be able to drive and cut at all times since offensively, that's all he can do. This led to the Jimmy Butler and Al Horford trades and is also why, at times, we've seen the 76ers stagger Simmons and Joel Embiid, so both have more room to drive.
Seeing the 76ers move other stars around just to accommodate Simmons' game means the Spurs would probably have to do the same if they made this trade. That means saying goodbye to Jakob Poeltl and Thaddeus Young for starters, despite their excellent defense and passing. It also means guys like Drew Eubanks, and even Keldon Johnson (should he still be on the team after a hypothetical trade) would likely play staggered minutes from Simmons as to not clog the lane for him.
In fact, it basically means, for spacing purposes, Simmons would have to play all or at least most of his minutes next to Bryn Forbes, Doug McDermott, Devin Vassell, and either Jock Landale or Lonnie Walker. Not terrible, but very, very limiting and certainly not as good as some of the units the Spurs could put together right now.