That said, how approachable that vocabulary is reflects how approachable the community around it is.
For instance, I've found the DevOps community to be very open and accessible to newcomers. There is shared language - orchestration, config management, even some acronyms like CI/CD - but they generally seem to use approachable language. I've also found the Python and Ruby communities to be very welcoming and willing to teach newcomers, and while I'm not involved in it, I've heard the Rust community really shines here.
On the other hand, one of the reasons I've stayed away from the security community is its propensity for acronyms. SIEMs, CSPMs, ASPMs, SASTs, DASTs, EDR tools, and maybe you've even got a CISSP cert.. It's not approachable, and I've found that many security practitioners wear knowledge of these acronyms as a badge of honor. I've found the networking community even more toxic: there are some pieces of software I've used for over 20 years, with forums I avoid like the plague, because many questions are answered with some variety of "Read the docs!" or "You don't KNOW?!?!"
If I were a benevolent-dictator-for-life and had to bootstrap a community, I'd be aiming to foster the former, not the latter.
Talk to anyone under 40 and they will tell you that mainframes are extinct, that Java is sooo old, COBOL: what's that? They could rewrite those dinosaur systems in a weekend's hackathon.
The problem is there’s no growth. There are no new customers, no new patterns or meaningful growth areas. It’s a career cul de sac, and when the bean counters at your big bank discover Oracle Cloud ROI is 6% more than you, you get nuked from orbit.
I work with alot of orgs that have these things, both directly and from a association/conference perspective - it's starting to change because the new CIOs didn't grow up with mainframes, and are finding themselves with no alternatives other than expensive and increasingly ineffective contracts to operate these things. 1990 was 35 years ago, the old guys are dead - the can has been kicked off a cliff.
That's even assuming you got an explanation in the first place that wasn't an "ask your systems programmer" or some other high level administrative gatekeeping cabal of the greybeard operator that is too scared of a new kid on the block wanting to learn how to IPL metal from scratch. That's scared me mostly away from working with most of this. I don't want to learn the code per se -- I want to work with the metal.
Interestingly enough, as part of IBM's Eclipz Project - to share tech between their server lines - the POWER6 shared a lot of things with the z10 mainframe processor. To quote Wikipedia:
"The z10 processor was co-developed with and shares many design traits with the POWER6 processor, such as fabrication technology, logic design, execution unit, floating-point units, bus technology (GX bus) and pipeline design style, i.e., a high frequency, low latency, deep (14 stages in the z10), in-order pipeline. "