Apple is changing the UI to accommodate new 'categories' that require a new organisational level. There is 'Your Music', 'New Music', 'For You Music', Radio, Connect. 'Your Music' is split into 'Library' and 'Playlists' (removing Connect elevates Playlists into the first category) Artists, genres, albums, etc. are subcategories of the 'Your Music'/Library category. Genres are subcategories in the 'New Music' categories. 'Apple Music Playlists' and 'My Playlists' are subcategories within Playlists. These subcategories are accessed via a dropdown menu. Different stations in the Radio category are represented by tiles as a playlists in the 'For You' category. Different subcategories in 'New Music' are represented by blocks with tiles within them.
There is method to this madness and a surprising variety in how different subdivisions are presented (to best suit the type of subdivision). If all these subcategories were individually selectable for the bottom row of icons, you would loose this hierarchy of categories and all would have to be presented via the same method (icon in bottom row). The hierarchy and the different methods by which the subcategories are represented (dropdown menu vs tiles vs blocks) would be lost.
I rather doubt that Apple will make more money from streaming than from downloads and at best that difference will be marginal compared to the overall profits of Apple. Streaming is what an increasing number of people prefer (streaming services are growing steadily while downloads stagnate). By offering it, Apple provides people with (a) what they want and (b) in a way that provides users with something extra that other streaming services don't offer: integration with existing personal iTunes music libraries plus potentially better ways of discovering new music and great playlists. This of course helps Apple (by stemming the losses to other streaming services and making their devices more appealing, though with Apple Music coming to Android the effect is more indirect by making the brand Apple more appealing) but it is also designed to help the user (via the iTunes library integration and better discovery methods).
Reducing this change to an attempt to reduce choice by Apple is an extremely narrow point of view that hangs its argument onto one small change (having to use a dropdown menu to switch between albums, song, artists, genres instead of an icon in the bottom row) and ignores all other changes in its narrative.