There's this annoying factor called 'Stickiness' that skews their decision-making. They have to prioritise retaining users because that's what makes them valuable. Any feature that increases stickiness will take priority over everything else. 

In Nostr, Amethyst can set a direction for itself that is different from Primal and not care about retention because the stickiness is much much lower here. I switch between the two all the time because both give me different kinds of experiences that don't necessarily overlap. I love it here on Nostr.