IMO, small ball didn't lose the game for San Antonio. There were other factors.
1. Taking Bowen out in the third with only three fouls. He left with 5:39 in the third and SA up 65-45. Kobe scored nine points and had four assists with Ginobili trying to guard him. There was no reason to take Bowen out. This wasn't a case of small ball, though, because they didn't take a big man out, they subbed a g/f for another g/f
2. Ginobili looked tired, forcing shots and bad passes. He was 3-of-13, attempted only two free throws and had four turnovers. A tired Ginobili is a bad Ginobili.
3. Parker took his foot off the pedal. In the second half, he only made one shot, which of course came at the basket. In the fourth quarter, he took four shots by my count, only one in the paint. When the Spurs offense goes through these droughts, often it's because Parker or Ginobili aren't aggressive offensively and creating opportunities.
When it comes down to it, San Antonio didn't look aggressive or energized in the second half. There was no urgency. Can we attribute this to old, tired legs after a seven game series? Maybe.
They sure don't help, though.