The problem is that sysadmin has the baggage of twenty years of that dude who deals with exchange and active directory. The rules for interaction with servers under the sysadmin label were terrible and quite frankly, so were and are a lot of the people.

There is a legal requirement (regulatory, but carrying force of law) for some industries to implement ITSM practices (and similar, don't quote me on specifics) . There is a requirement in those practices that Developers not have access to production, and that Operations have access to the code. That's incredibly wrong. It's misguided in the worst possible way - The point is to make sure the two audit each other, but it requires black box auditing, when you actually want whitebox auditing. (Note that allowbox and denybox are not acceptable substitutes here).

SRE is called SRE because of a difference in those practices. DevOps is an inexpert redevelopment of those practices. Sysadmin practices evolved into both, but what's modernly called Sysadmin is descended from the AD and Exchange people, and have bad practices. You can't walk back the evolution of words, you can fix them through evolution as well, but it's as slow or slower than getting there, because the ecological niche is already "filled"