There is a problem with returning to average - it is eventually a self fulfilling prophesy, but the problem is it can take a lot longer than you think.
What about a casino roulette wheel? Over thousands of spins it will also 'return to average'. Lotto numbers drawn will also do the same but you can't build a strategy around it.
I agree it can take longer than one thinks, you can't predict the future, after all. But I think it is not correct to compare price movements to roulette or lotto as price movements are never completely random, therefore the things that affect each are completely different.