I'm not worried about whales leaving. There are a few that I know that are pretty cool, but others? Ehh, the blockchain will go on. A certain whale rage quit not that long ago, and steem didn't even blink. Of course, he still runs his bid bot here, and has someone running his witness node, so he's still making profit from here. We just don't have to deal with him as much.

Tons of people have quit and gone inactive in the last year. Maybe some of them will show up again...but we kept going. Did any of us really even notice when various whales just stopped posting for months on end?