The goal of DevOps was to remove those gates and silos. It was meant to be about skills over roles.
All we appear to have done is change the tools and role from that of a SysAdmin to DevOps engineer.
1. Core infra
2. Anything related to security
Outside of those, we all can and do work on everything else. We regularly coach people in terraform and third party APIs to endure they understand that they own their application lifecycle. They control the entire SDLC and we work together to ensure sanity. There are lots of bumps but nobody gets a pass on understanding the in and outs of software development and management. I can't see a cloud based offering being successful without that.
Who is doing what wrong, according to whom?
Software complexity expands to fill available resources. Only, in this case the available resources are manpower rather than hardware.