There's no doubt the 2019 Mac Pro will make many people's tasks faster. The question is: Do they absolutely need it to get their work done.
That’s ultimately for them to decide.
You seem to be needlessly obsessing over the term “need”, and appear to be stuck in some sort of cognitive dissonance loop where you have convinced yourself that the Mac Pro is redundant because any potential customer would either have already migrated to windows or would get by just fine using a lower-end Mac product.
In a sense, it reminds me of all the posts by people claiming how the ipad will never replace a laptop because of a certain limitation. Which to me is disingenuous, because not everyone is affected equally by the same shortcoming.
Instead, it would be more meaningful to discuss the strengths of an ipad and highlight use cases where it excels in, so users can make an informed decision as to whether they should get an ipad to do whatever it is they want to do, or opt for something else. And the reality is that there are many people already using iPads for work (and play), for a variety of reasons.
Likewise, I feel that the word “need” here is a red herring and ultimately disingenuous.
Rather, what would be more meaningful is to showcase how much better workflows are improved by a Mac Pro over the next best alternative, and let consumers make an informed decision as to whether they would benefit from getting one or not.
For example, the writer of the article linked above has this to say about the Mac Pro.
A complex multi-layered 8K Export takes 3 hours and 29 minutes on the iMac Pro whereas it only takes 1 hour an 40 minutes on the Mac Pro.
This is a very real, quantifiable example. It shows, rather than simply tells, how the Mac Pro improves his workflow. Users can then decide for themselves whether the time savings is worth the extra financial outlay, and whether they absolutely “need” one.
And even if it’s just an irrational want, there’s nothing stopping them from enjoying the perks nonetheless.
