The fault of fragmentation lies at many levels, including distributors. The bookstore at my alma mater in the Midwest is normally great at promoting modern tech products, but they recently started pushing two models of a phone with KitKat at $100+ pricepoints. That's Android 4.4, which was deprecated in 2015. Who are these phones for? They're not even suitable for computer science students, because trying to learn Android development with a KitKat device is incredibly suboptimal.
A google search on 100$ android phones returned a "best cheap android phones" list. The first entry is the Nokia 2 (never tried one but I heard good things).
For 85$ it ships with Oreo.
That's kind of amazing : for a relatively modest sum, you get a lot of technology.
It makes me wonder why anybody would recommend a costlier device shipping with 4.4
