How has the military (US, or other) historically managed to recruit and retain their medical corps, or the Army Corps of Engineers? Has there just not been a situation in modern memory where there weren't doctors sufficient to keep the gears of war turning?
I've worked with quite a few Federal and DOD "hacker" types over the years in the capacity of a hacker in the private sector. The impression that I have is such that your average ruck-humping Joe will not be able to do it, but it's not so special (as contrasted with a civil engineer or doctor) that you couldn't take high-aptitude recruits and bootstrap their knowledge to a sufficient operational capacity in the amount of time as a typical post-boot AIT timeframe as you might a Corpsman or linguist.
Our not-quite-aptly named SOC would routinely engage in legally grey operations to disable cyber-criminals servers whose hosting providers were non-responsive to our standard, legal course of take down. The majority of the staff had a Bachelors in an unrelated domain, several with an associates in general IT work, and a few with nothing more than a programming bootcamp.
The tale that we're so special as to not be meaningfully draftable is, I feel, egotistical.