And how many consumers really would be bothered to screw around putting it together?They'd be better off shipping the CPUs and the IHS separately in the box and allowing you to choose your desired TIM during installation.
If Intel did this you and others would complain Intel is not selling a complete product.
There is nothing wrong with the die-TIM-IHS packaging/design with the Skylake-X as it looks fine to do 4.5GHz all cores on a powerful air cooler (such as Noctua D15), this is good enough for most buying this product and you still hit 4.8GHz with the AIO without delidding on a 10C.....
Still substantially better than what we see with Ryzen that is soldered.
I think Der8auer sums up the attitude and criticism quite well after his testing, who is one of the top league overclockers internationally.