I suspect those who would leave unhappy are the people who did NOT invest any money, so the power-down doesn't really apply to them. I guess there will be a whole lot more people who try to EARN their Steem rather than BUY their Steem, so the idea that they will not say anything bad would apply to a relatively small number.

Personally, if I had loads of money invested, I wouldn't even worry about making any money from author or curation rewards. I would be focused on building a sustainable platform so that it goes mainstream and raking in the absurdly huge rewards from the rising value of Steem.