[bokumo]

I don't think you're being fair to Chris Penner. He ends his blog post with: "It may take me another 5 years to finally finish it, but at some point we'll continue this journey and explore how we can sequence effects using the hierarchy of Category classes instead." Emphasis by me.

So while it is true, that what he has described so far is not sufficiently powerful for normal programs, he has clearly stated that there are more abstractions between Applicative and Monad to explore than what he has presented so far.

[internet_points]

took a bit less than five years :) https://chrispenner.ca/posts/arrow-effects