I'd only be concerned about this if the price ran up with no corresponding change to the platform. If the price runs due to the issues I mentioned getting fixed, then I'd be more than happy to buy up as much Steem as those whales want to drop.
There's a lot of built in incentive to keep your steem in the system. Right now you can easily make 24% returns on your money and you're not going to find that anywhere in the current banking system. If you're a whale and you can live off the money your steem is making and the platform is sustainably increasing in popularity and usage, there'd be a very strong pull to not move your investment anywhere and to instead just reap the rewards of it.
That's even more true now that you can actually just power down a percentage of your steem instead of having to power down everything.