Because the blog post clearly indicates that some things that were going to be possible in the NPR build in shader are now going to be instead done with tie-ins with the compositing system.
Other elements that were already working in the NPR build may or may not be possible, or as elegant (such as screenspace effects) due to the new requirement that things have to work with Cycles. Specifc example mentioned by Clement, here.
The entire paradigm of “why not just do this with compositing” was brought up a full year ago, and I believe the case was effectively made that compositing is not an equal substitute.
These questions went completely unanswered.
A lot of care has been taken to ensure that still the same results can be made.
I’ve seen no examples of this. So test images which show this (more than a monkey with a checkerboard shader), would be welcomed. The killing of the NPR prototype was announced in late May, and Clement has said nothing in the thread since 8 days after announcing he was killing it.
One looks at how much was working in the NPR protoype, and how few things were left on the TODO list - and wonders if we’d already be close to a final release if it hadn’t been killed 6 months ago.
So the complete lack of updates and communication on this - that’s a big factor in people having concerns and doubts. Combine that, with various regressions in Eevee Next that have been completely ignored for 12-14 months… skepticism should be expected.