There was a later comment that said it would be "a 2019 product":
https://www.macrumors.com/2018/04/05/apples-revamped-mac-pro-to-launch-in-2019/
Yes, but who cares - the claim is so non-falsifiable that its almost a tautology. The idea that Apple are
considering previewing something that they've described as "a 2019 product" at what is usually their major press event of the year is one for the
International Review of Papal Denomination (incorporating The Journal of Urso-Sylvanian Scatology and
The Role of Constipation in 19th-Century Detective Fiction)".
Too late. They've already got it wrong by not having had a viable high-end Mac workstation for 5+ years.
If they had a viable mini-tower Xeon Mac with PCIe graphics, they'd solve 90% of pro users' problems and have all the time in the world to do something innovative.
10-15 years ago, such a machine - esp. at PC-competitive prices - might have cannibalised sales of iMacs and laptops, but today only pro/enthusiast/hobbyist users would consider such a system - and any such users who
aren't prepared to pay a premium for MacOS have already jumped ship or built a Hackintosh.
They've also apparently decided that the "Mac Pro" is exclusively for people doing VR or cinema-quality video on cinema-quality budgets, and that people who prefer a desktop for flexibility and customisability without necessarily needing a 16 core Xeon and workstation-grade graphics can go whistle.