The reason for curation is token distribution. Without curation, Steem would be in the hands of a few people and never would have been distributed far and wide.
Bitcoin is distributed via miners with open access.
ETH started as ICO + POW; this was their token distribution model. They are going to PoS in which people lock up tokens to secure the network in order to get more tokens. While, not the best distribution model, since ETH has already been disturbed far and wide, they can maybe achieve a decentralized token distribution. However, unlike with DPOS (Steem's consensus model), token distribution isn't nearly as important to the functioning of the ecosystem because there is no stake based voting.
Now, enter DPOS. With DPOS token distribution becomes absolutely paramount, because tokens have voting rights for witnesses that run the blockchain. If you remove curation rewards what you are left with is a "shotgun DPOS" model which is basically a lazy PoS with voting rights.
Shotgun DPOS = Instead of passive token creation, you must manually upvote 10 times a day (vote selling/delegation to bidbots)
Removing curation rewards means removing the incentive to distribute the token and self-voting will be the 100% play in game theory.
A DPOS system with poor token distribution might as well be a centralized database. Sure, you get a lot of benefits of blockchain but the trust element goes out of the window.
Now, if you want to remove curation you would need to remove the upvote IMO because it becomes an obstacle. Just call it how you want it, remove author rewards and curation all together and have the inflation go to interest paid to SP stake hodlers. Make the staking rewards liquid so you can just donate to content creators you want. It is the same thing, forcing people to upvote with low curation rewards is just a janky system.