Why would delegating to a curation service be something they would do?

Because blind vote selling, undeserved self-voting, and farming using multiple posts or comments will all have a lower return than sensible curation and also has a higher risk of drawing downvotes. even further reducing the return.

Curators can right now earn quite a bit more then bot delegators and that doesnt really mean anything

Not on any sort of large scale. A few small curatiors might be able to do it. Might. Even that is hard to say because of things like being systematically trailed by a larger vote will throw off the statistics.

In broader terms the 4x-5x difference between self-voting and curation is too wide for curation to have a chance to keep up, which is exactly why there is so much pull toward self-voting and vote-selling and so little curation, therefore little chance for creators to earn much. There is still some legitimate curation, which is altruistically-motivated and admirable, but not a sound or effective basis for the system as a whole (and also likely not sustainable, as even many altruists will ultimately give up as they question why they alone should continue to carry the weight for everyone else, particularly on a system that, despite their admirable efforts, is not working very well overall).

There are downvotes.

I did not claim none, I wrote "almost NO downvotes". The statistics I have seen are 0.01% to 0.1%. That's close to none, and in any case nowhere near enough to place any sort of meaningful deterrent against or remedy for milking. If you want rewards actually paid out where the might do some good instead of milked by self-voting and vote-selling, the only way to accomplish this is by encouraging more downvoting.

fear of retaliation is why you arent seeing much towards the community downvoting

It is both, as I explained above. Yes there is fear of retaliation no doubt. But there is also the cost reason why people do not downvote. Reducing the cost will encourage more stakeholders, most of whom are not malicious trolls, to make use of the downvotes.

Putting in minimal effort required to eliminate the chance of a flag)

Eliminating the chance of a flag is easy to do right now, because flags are only 0.01% to 0.1%. We need to try to increase downvotes to the point where minimal effort to avoid them is not so easy. It is true this won't necessarily be successful because we don't and can't know without trying it how much people will use cheaper downvotes even though they are still unrewarded/uncompensated effort, and still risk retaliation. But it is well worth the attempt to try, because this is the only way we are going to find out. If necessary, we can iterate further, something which the Steem platform has sorely lacked in the past as we've sat around circle jerking while the whole thing circles the drain. We can't afford to do that any more.

People will continue acting the way they act right now

People (by which I assume you mean stakeholder voters who are now largely milking) who continue to act as they do now will see their earnings decline because the current behavior is not as effective, if at all effective, under the revised rules. They will lose out to those who optimize to the new rules. Since they earn less, the creators (and other non-milkers) earn more. This is inevitable, whether you choose to acknowledge it or not.

No behaviors will change and all that happens is that you took from creators and gave more to big SP holders.

You are not understanding that the current system is broken and creators aren't making much already, with prospects for the future on this path looking more and more bleak. The reward pool is being milked out leaving little to nothing left for creators. By using economic incentives to encourage voters to support curation (even if they don't do it themselves) rather than self-voting and vote-selling, creators stand to get more than what they are getting now, which is, increasingly, little or nothing.

Percentages don't matter one iota if you don't get votes (without paying for them) because stakeholders just use the votes for milking instead.