What you state is not true at all. Minnows make noting from curation. This is because with their small sp they do not get even 0.001 steem. A boost to 50% would help, but curation rewards would still be unreliable and subject to big loss from rounding. It currently takes about 100sp to reliably get some small curation rewards. Everyone below that is effectively excluded from curation.

When I started i made literally 100% from author rewards. The change will certainly hurt minnows.

Furthermore a 50% curation reward does not realign the incentives. Self-voting is still better than curating content. Right now it is possible to make money from curating, but that only when you place tiny strategically places votes. With 50% that becomes a bit better, but nowhere close enough to make a positive change.

Curation is a game and there are strategies to maximise rewards. But fundamentally it relies on the willingness of some people to forgo this optimum strategy and reward good content. That can be proven game theoretically.
Now the system can be set up in such a way that a good strategy is to follow these few nice people that break the symmetry of the game and amplify their vote. 50/50 could do that, but at the same time it hurts the producers that the nice people want to reward. Reality is complex and we probably need a statistical simulation of participants to see. My impression is that 50/50 will not be better and feels even more artificial than the 100/0 which is simply a pure tipping system.