How can those of us in science and technology support the humanities more?
There was a famous post, "Don't Become a Scientist!"[1] about Physics in particular.
It includes the memorable line: "I have known more people whose lives have been ruined by getting a Ph.D. in physics than by drugs."
Which I suspect tells us more about Katz's social circle than anything else but nonetheless shows that it certainly isn't a rosy wonderland in STEM.
I feel a lot of the answer of "How" will be in the "Why".
If area/endevour is not seen as producing value or being rewarding, it'll naturally atrophy.
If we have a compelling reason for Why that area is rewarding or producing value, it may need as little as an informational/awareness campaign to promote that value/reward.
(note that I am NOT defining "producing value" in dollar terms necessarily, but more generically as "something that somebody or society values". Otherwise, it becomes "something you do for fun for yourself", which is an awesome hobby and everybody should have some, but may not necessarily need to be externally sponsored. I.e. I pay to play music and paint and photograph as a hobby, other people are paid to play music/paint/photograph/etc, and I'm not sure either model is the only right model).
I notice the Historian PhD's only track is defined in that article as somebody who will teach history, not as somebody who will research/write/promote history. This makes it a a very small subset of what I would've considered a Historian / History PhD, and as such, again, I return to "Why" they may need external support if their interaction is strictly inward/cyclical.
Honestly? Don't shit on STEM courses. Encourage programs that produce well-rounded students in the liberal arts tradition.
Most humanities departments are dependent on class enrollment - they are so-called "service" departments (vs. research or clinical departments). Enrollment is largely what determines what those departments can support.