So earning enough money to have a significant amount of sp (let's say 10-50k) is easier than creating a post ?

I have to disagree with your position. Buying the stake that backs up the vote does cost in real life (or at least it should) and keeping your resources staked also has opportunity costs. There must be some balance and right now we have a 3 to 1 ratio in favor of author rewards vs voting. Content creation does not carry the financial risk of losing the value of an investment. A 50/50 split seems fair in my view as long as the right content is rewarded.

What I am not in favor of is reducing the rewards pool to fund the SPS, the funding should come from the portion of the inflation that is allocated to SP *"interest"*. As a stakeholder am willing to forgo that income stream if it goes to projects that end up increasing the value of my holdings. According to some witnesses [they are discussing that option](https://steem.tokenbb.io/topics/thecryptodrive/tokenbb-topic-sps-inflation-funding-split-prop-1560906423422) (and I hope they give it a serious consideration).

Nope, it doesn't, and in an ideal world we might just go right ahead and give 100% to authors.

But in the real world we need a system with sound economics in order for authors to be rewarded at all and that _requires_ the curation share to be higher (indeed maybe even higher than 50%, but we are hoping for various reasons that 50% is high enough to work).

Think of it as a necessary evil if you prefer, rather than the straw man of someone making a claim about equal skill, sweat and effort, because no one is making that claim.