Steemit is about rewarding content creators, that's the primary goal of steemit.
That is one goal. It is not the "primary" or only goal. Curation is indeed an important factor and we know that the original split in rewards was 50/50 for content and curating. Voting incentives are just as important to the goals of STEEM/Steemit as content creation are.
But as I said - the market for content consumption is exponentially larger than that for creators. The user base can expand much more and much more rapidly by incentivizing readers and voters just as much or more so than content creators.
More content creators will earn rewards with a proposal like this...
Based on what data? If you have no incentives for readers and voters, why would they care to buy in, power up, and spend time curating? How many people do you think will pay to use social media, which is free on many more user-friendly and wildly more popular sites and apps?
Not everyone is a blogger. And if you have only a community of bloggers, it will likely be small and the bloggers will likely spend more time on creating than they will on curating.