Yeah but let's be real, they pretty much never call that a walk. Regardless, even if they whistled Allen for a foul, there were still a number of scenarios in which the Spurs could have still lost. As others have mentioned, that was far from the only reason why they came up short.
Normally I would say series over is like the rest of you, but this is a veteran Spurs team... not the Oklahoma City Thunder. I don't think it's a foregone conclusion that the Heat win.