I doubt this redesign is driven by product managers creating work though (not that that isn't a real phenomenon) but the more insidious effect of the attention economy. Leaving users to drive and curate their own experience doesn't match the "engagement" you can gain by endlessly shovelling an algorithmically optimised feed of content into their eyes and ears, while they endlessly scroll. And the more control you have over what content is being seen, the more effectively you can monetise it by prioritising whoever pays you the most.