If Apple honestly say "we couldn't care less about professional users, we're making money hand over fist anyway", then at least we all know where we stand. Apple haven't taken that approach - they keep making grand overtures about how much they care about professional users. They keep making grand promises about how the perfect professional machine is just around the corner, how they're not updating the current machine because the next big thing is so incredible, amazing, awesome.
There are a lot of very loyal Mac users who have kept Apple in business through thick and thin, but their patience has been tested to breaking point. Those users have been a key part of Apple's marketing; Apple make computers for dreamers, visionaries, artists, the cultural elite.
I don't know anyone who is genuinely happy about being a Mac user, but I know a lot of people who grimly tolerate giving Apple their money. They know what to expect from next year's Macs - they'll be thinner, lighter and subtly worse in a lot of important ways.
What happens to the Mac brand if those users leave? What happens if the resentment felt towards Apple by photographers, video editors, 3D artists and recording engineers turns into a full-scale revolt? What happens if owning a Mac marks you out not as a sophisticated member of the cultural elite, but a nerd who wants a slick *nix experience or a sucker who paid $2000 for a Facebook machine?
Apple are playing a dangerous game. Apple don't need to care at the moment because the iPhone is so gratuitously profitable, but they should know better than anyone that the market is incredibly fickle. They're burning decades of goodwill for no obvious reason.
It wouldn't be particularly expensive to make the majority of pro users happy. Bring back the old cheesegrater Mac Pro and stuff it with the latest commodity components. Bring back a previous-generation MBP chassis and fill the extra space with an i9 or a Xeon E3, four SODIMM slots and a GTX 1070 Max Q or a Quadro P5000.
They don't have to promote these machines, they don't have to display them in Apple stores if they're ashamed of making a functional computer, they just need to make them and promise to keep making them to secure the continued loyalty of their most loyal customers. Apple won't do it, for reasons known only to them. In the long term, that could prove to be a very expensive oversight.