> but critically, it needs to adapt to its users – to people!

In principle, I want this to be true. But, in practice, I think products change because the teams that built a product need to justify their continued existence within a corporation. Slack's last few rounds of UI changes for instance, has been a net negative for me, the user. Why can't I split several channels in the same window anymore? Why did they add a thick vertical toolbar that I don't use and can't remove? Not for my benefit, that's for sure.

p.s. Kelley not Kelly is the correct spelling of his name.