Maybe it an anomaly and maybe it isn't (I can't predict the future), but I know the growth was real. If I bought stock 5 years ago and sold it today, I could pocket those gains.
That is the problem with looking at private company valuations and trying to decide if they are good investments or not. You don't know how the story is going to end for the common shareholders and what the overall return is going to look like. I'm not saying the upside wont be there, it very will could be, but the level of risk is still much much higher than the big public tech companies.
AMZN’s current valuation does not assume 0% future growth. It already assumes exceptional growth and expanding margins. Amazon has to do better than that for the valuation to increase.
I am not saying that Amazon is a bad company, or working there is a bad idea. Just that reversion to the mean is a powerful force.