wouldn't the 50 / 50 be the ideal scenario to sell their votes?

It depends, curation has a curve that can reward you rather well depending on how good you curate. I've had votes valued at $1 giving me back SP worth $1.1, etc. with 50% this could mean a $1 vote could return me a vote of $2.2 or more since more. Not 100% sure on that but just what I'm thinking.

About the newcomers it will depend on the quality and resteems. If someone or a curation project finds a post from a completely new user at 0.00 rewards and they give it a $10 vote and it ends at $500, they can earn a lot more rewards than if they had given themselves the $10 vote which half would be shared with other curators, or no one in case they are the only voters they'd only get the $10 back and wouldn't make $50 instead since no one else thought they had content worthy of upvoting.

It's a bit technical and theoretical at the moment but I don't think it would hurt trying it out, especially not now here at the bottom with the least active accounts and a price that can't get much worse than it is now.