It was amusing to note that during this 2nd MacPro "status meeting" that the Apple brass recommended "Pros" buying a new iMac Pro if they needed a computer now instead of any of the cylinder trash cans.
Only they didn't. direct quote from the article.
"... customers are waiting to spend budget on, say iMac Pros or other machines, they should pull the trigger without worry that a Mac Pro might appear late in the purchasing year. .."
https://techcrunch.com/2018/04/05/apples-2019-imac-pro-will-be-shaped-by-workflows/
Yes the iMac Pro is in there but just as equally there is "or other machines". The notion that they are herding folks exclusively into iMac Pro is baseless. Note that 'machines' is plural. That can't be a reference to solely the MP 2013 model.
It is highly likely there will be some overlap between the Mac Pro and iMac Pro both in price range and capabilities. All the more so when customers don't know what the price and capabilities of the Mac Pro will be. What was present was customers guessing at the overlap extent and price range extent and coming up with a muddled fiscal planning. For 2018 there is no overlap because there is not Mac Pro 2018. That's the only problem being solved here.
In 2019 there extremely likely probably will be overlap at least in price and probably also in capabilities in certain dimensions (e.g., use the same CPU SKUs in both products. ). However, customers will have the info on both sides so they can figure that out for themselves. This year they are not getting 'Mac Pro vs. iMac Pro' info in time to make Q2-Q4 purchasing decisions in advance.
The trash cans are mere placeholders now....(though the low end 6 core trash can would make a kick ass (though large) MacMini replacement).
I don't think Apple has any expectation for the MP 2013 other than it will bleed off at roughly the same rate it has for the late year after the price cuts. That's it. That is a rather expensive alternative for a Mac Mini.
Apple probably expects that most folks who would have previously bought a MP 2013 would buy an iMac Pro. that would still be true next year when the Mac Pro is shipping. (and the MP 2013 gone).