I work as a SRE and have done a lot of platform engineering in my life. I call the sysadmins you're talking about "operations". This role proliferated because system administrators/engineers that were coding were paid the same as a SWE while ops people came at a discount. Every contracting and consulting firm ever had an "ops as a service" contract that they'd offer large businesses. This was the norm for a little over a decade I think. Things have changed now and it's harder to exist in the SRE space if you don't code, but finding people who know systems, infrastructure, and application code to a high degree is pretty difficult and, again, comes at a premium. This is the result of more companies reaching scale that cannot survive on blueprint infrastructure and lifecycle designs, and things like tooling mattering so much to DevXP. Companies see the value in people who work on this kind of stuff now.
A lack of gatekeeping I don't think was ever the issue; the incentives were just perverse.
I spent time working around the space industry. Almost a decade of my life.
The big contractors in aerospace have a _really_ difficult time finding people who know enough about the hardware and the software to be competent engineers. They’re basically unicorns.
Not that they don’t exist, but if you’re looking for someone who is demonstrably good and has a validated educational background in both, you don’t have a huge pool of talent to go with.
So they hire them when they find them, but they also just tend to hire experts in each field and let them collaborate. They didn’t try to reinvent the wheel with some new “paradigm shift”.
A lack of gatekeeping I don't think was ever the issue; the incentives were just perverse.