The concept of the EIP is about the combined effect of three changes, not just this one. The idea is to make desirable behavior more profitable, and negative behavior less profitable. Currently it's most profitable (and easiest) to delegate your stake to a bidbot and not even play, which is what many large stakeholders are doing. If it becomes more profitable to actually curate content, people will do that. That means more rewards for good authors, and fewer rewards for bidbot delegation (or self voting) and people who choose not to participate. So - if that goal is achieved, more people curating will in turn lead to more good content and people actually being rewarded for that good content. A small portion of 'free' downvotes is a piece of this puzzle.
I think if people are more likely to receive rewards from the effect of stakeholders participating, they will be much more likely to stay. If good content is being appreciated and curated, people will be more likely to stay. It's part of the value proposition of proof of brain and the current economic incentives don't fully align with that original vision. The EIP attempts to bring us back closer to that goal.