That's only true if the price of robots doesn't decline rapidly. Which (I believe) it is, and like virtually any other technology, will continue to do.
Even if not, we don't need that many people to open doors. So perhaps an office building will have 2 human janitors and 10 robot janitors; it doesn't really change the problem caused by souped up roombas putting the vast majority of janitors out of work.
Even if not, we don't need that many people to open doors. So perhaps an office building will have 2 human janitors and 10 robot janitors; it doesn't really change the problem caused by souped up roombas putting the vast majority of janitors out of work.