I think I'd agree that "most important century" is a twistier and more confused claim than first appears, but I think it's ultimately dissatisfying because it's a tautology, and we should not deny tautologies. They're always true, and sometimes they're even meaningful.

It is true for me that this is the most important century, in the sense that the most important thing is whatever thing I should be paying the most attention to and trying to affect.
Ask me again in 200 years and I will probably tell you that the 23rd century is the most important century at that time. It will be an honest report. That's what will be important to me then.

I don't think there is any use for an objective, timeless sense of what is "important". It should depend on the reference frame. Different people should find different things important. The denial of that, the striving for a monocausal, monofocal global discourse, has been causing many discursive and interpersonal problems, and might just be an artifact of a smaller and less connected human umwelt that we departed from long ago.

The more I think about this, the more I think there should not really be a distinction between Differential Progress and progress studies in general. When we study anything, we should always be thinking about how we should take agency over it. Knowledge is supposed to be used to improve the world.

Or... would a good paraphrasing be "applied progress studies"?

My own sense is that, yeah the Success brings obligations section is most of it. To add to that: It takes about 10 times as long to realize a design or to propagate or empirically validate a theory, than it does to conceive it, and the one who conceived it is often best positioned to do that work.

Founders usually become maintainers.