Apple wants to onboard people into the new Apple ecosystem, which is iToys and backend services. They believe this will be better for you, not just for them. They control the iOS-based world in a way they could never control "computers". They're trying to get as many people as they can into their new Disneyland-ish ecosystem, where everything you do is approved and monitored and everything you buy is bought through them.
The low-end Mac seems to only matter now as a source of low-end users, who need carrot and stick to move them off Mac and onto iOS, so low-end Macs won't get better but low-end iOS devices will. I suspect we'll see touchscreen laptops running iOS pretty soon, and that will signal the end of low-end Macs.
The high-end Mac users have a better story, because Apple needs developers for their ecosystem, and those people need good tools. I can't imagine Apple being interested in developing dev tools that run on non-Apple devices, and I think they'll want an absolutely guaranteed source of computers with whatever features are needed to develop the best stuff for their ecosystem, so I think a high-end Mac product line will live on with each new version being a bit more iOS-like. If they want to keep the lockdown on iOS while retaining full power to develop for it, they will probably have to keep the less-locked-down macOS going for dev machines for a long time, but things like the Mac Mini have no place in this picture.