I like that variations of the word “intellectual” appear 13 times on this page

No it is not.

Bluesky already matches the old Twitter experience, enough to be a true 1:1 Twitter replacement for many users to migrate to.

If you use Twitter, then you have learned 90% how to use Bluesky already.

Other than that or Threads, the rest (including Substack) are not even close. UX familiarity is the point.

But how am I supposed to doomscroll on Substack?

There’s a short Notes feature now which mimics Twitter (Substck links got banned from Twitter after they released the feature)

Not enough content to doomscroll yet but seems better than direct copycats in long run

I mean, (a) see Betteridge's Law of Headlines, but (b) I think this illustrates a common confusion about Twitter. Twitter was many things to many people. If you used it mainly to consume the ramblings of self-important bloviators, then, yeah, substack might be a substitute, but that’s not what everyone used it for.