Are you sure about that?
2c/4t, 4c/4c, 4c/8t is a fairly logical lineup. With the addition of a 6-core in 8000-series, they were kind of stuck in terms of lineup (4c/8t is faster than 6c/6t in several situations, relegating what is effectively i7-7700K to i5 in less than a year would look bad etc). 4c/4t, 6c/6t, 6c/12t is the best they could come up with.
Now, with the addition to 8-core in 9000 series Intel did have a perfect opportunity to match AMD-s offerings in terms of threads. They did not. We do know that all 4, 6 and 8-core do have HyperThreading in hardware but it is disabled in everything except 9900/9900K. With MDS and mitigation effectively being "disable HT", I really do suspect it is not a coincidence.
I am not saying that it is definitively so but it looks like a valid theory, no?