This is effectively a restatement of my premise, though I think you're also missing the larger scale of non-social (epistemic, marketing, advocacy) roles.
When Twitter was small, it didn't offer mass-scale socialising. What it did offer is far more comparable to Mastodon now.
When Twitter did develop sufficient critical mass, at least within a specific context, it became compelling in ways that compensated for any onboarding difficulties. That occurred in niches initially: tech early-adopters, the Arab Spring (a/k/a the Twitter Revolution, seen then as a Good Thing), and in particular, journalists, who live and die on hot takes and quick access.
(I'm watching the accommodation of the latter to Mastodon / the Fediverse with interest and amusement. Some factors that created strong appeal on Twitter are (still) lacking on Mastodon.)
When Twitter was small, it didn't offer mass-scale socialising. What it did offer is far more comparable to Mastodon now.
When Twitter did develop sufficient critical mass, at least within a specific context, it became compelling in ways that compensated for any onboarding difficulties. That occurred in niches initially: tech early-adopters, the Arab Spring (a/k/a the Twitter Revolution, seen then as a Good Thing), and in particular, journalists, who live and die on hot takes and quick access.
(I'm watching the accommodation of the latter to Mastodon / the Fediverse with interest and amusement. Some factors that created strong appeal on Twitter are (still) lacking on Mastodon.)