General purpose computer platforms need to be inclusive of a wide variety of users and use cases, or they're on the road to not being general purpose anymore. Apple has now cut the Mac platform off from all users and developers and applications dependent on truly high performance IO, and that's not good.
Sure, that market's smaller than it used to be and may not represent a huge amount of revenue for Apple, but it didn't have to be expensive for Apple to keep the Mac relevant here. All Apple ever had to do was continuously make boxy Macs with lots of expansion slots and storage and IO and sell them for a reasonable price. Wouldn't have cost much engineering time, and it would have been money well spent. Had they done this instead of replacing the entire product line with the misguided moonshot attempt that was the 2013 MP, we wouldn't be having this conversation today - I bet Mac Pro would still be a lucrative and influential product, and they wouldn't have decided to put it out of its misery.
Deciding that it's fine is spin. The truth is something like "They carefully aimed the gun at their own foot, pulled the trigger, let gangrene set in before going to the doctor, tried desperate measures, but eventually had to have the whole leg amputated" and you're making that into "They've chosen to go monoleg and not even bother with a prosthesis and that's a great thing, actually!".