The idea wouldn't be to take away rewards from people that don't have big followings elsewhere and I don't think that would happen --there'd still be plenty of opportunities for good content creators who don't have followings elsewhere to rise to the top. The tradeoff for those people is different though; less distribution elsewhere means a lower break-even point to use Steemit (and lower rewards necessary to keep them as a result).
The idea is just to incentivize different types of users differently -- I think Steemit has done a great job so far aligning incentives but always room for improvement (if goal is to make this thing as big as possible).