What are you talking about? After HF 21 any amount of stake is more valuable than before. That's because curation rewards go up by about 80%. If you curate skillfully, which means front running large votes and finding new content likely to attract a lot of votes, then you can earn much better curating after HF 21 than before.

You see, the non-linear reward curve stuff applies to rewards earned by a piece of content, not votes in themselves (except when you're the only voter on a piece of content, of course)!