Elimination of curation rewards would not stop the vote selling. Vote selling is a direct monetization of the voting power (where the voting party receives some or all of the expected author rewards in advance of their vote). Since it's a dutch auction style format each voting round, the price of upvotes is actually set by the buyers.
Increasing the curation rewards will decrease the amount vote buyers are willing to bid for upvotes. Since the curation portion of the bid-bot revenue model is much less dependable than the buyer bid (and would continue to be undependable after a move to 50/50), increasing curation rewards would actually decrease the profitability of bidding bots, encouraging voting power and delegation to move to actual curation.