Great article. Even if the figures you mention are STRATOSPHERIC regarding curation revenues (minnow perspective), I love the idea of the theory

Curation is a game for whales and dolphins. Minnows should stick to posting and commenting

But does it say that Whales should post less ?

The current situation is that whales DO curate, but mostly DO post.
Simply because the self-upvote and their followers guarantee them a significant ROI.
We therefore see what I would call "bad" behaviors:

• the new whale trying to milk it until the last drop posting stories on how he or she got rich in 2 days and how she now is a Steemit evangelist
• Whales-authors, writing for minniow and giving back some revenues... but never steem power

It gives literally no chance for minnows to earn dignifican amounts on a good story.

Should steemit refrain such behaviors, allowing more "power" for minnows to post ?

I agree on the comments being a great way for minnows to build power. But in the end, the ecosystem should not discourage minnows from posting quality content.
For the record: yesterday, my "sleeping beauty" picture (cool pic, a bit on story on the place where it was shot etc...) struggled to make $4.... while a comment where I gave all my SBD to a charity brought me $8.
At this stage, I will consider that $4 is great, and I will write more about my trips because people seem to like it.

My 50cents.
@sebastien