Here are some slides from Michael Mandel, he says yes it was an illusion. Matt Yglesias has a good summary of his argument. Median wages were stagnant, the stock market was down, and health care costs were rising, without necessarily translating into better outcomes. Mandel argues that the current collapse in part stems from the revelation that productivity growth (and no, he doesn't trust the reported numbers) was low all those years. On top of all that perhaps productivity growth in finance was overstated as well.
My take is this: there was some productivity growth but much of it fell outside of the usual cash and revenue-generating nexus. Maybe you will live until 83 rather than 81.5 and your pain reliever will work better. In the meantime you will read blogs and gaze upon beautiful people using your Facebook account. Those are gains to consumer surplus, but they don't prop until the revenue-generating sectors of the economy as one might have expected. Given that, the rest of Mandel's argument can still work, whether or not you think the productivity gains were a mirage in some absolute sense.