Part of the problem is that senior management in many organizations is so damn bad at, well, organizing the organization. Both the people and the software architecture. There really is something to an approach like everyone credits to Amazon: small team with a discrete product and proper architectural boundaries, communicating to other applications in known predictable ways with a proper process on both ends for making changes.

When you do that, a team can just go. Instead, in many places there's all this bullshit about "Application X is built by Team A, but Team B and C will do the QA." Or "Team D is in charge of Applications Y, Z, and Q, so they can't get to your feature request for Q this PI, because they've got high-priority work for Y and Z." So now you've self-blocked all work on Q just by screwing up your org chart. And we haven't talked about the fact that Team A is in the US, Team B is in Europe, and Teams C and D are in India, so now let's add time zone nonsense to all of the above stupidity.

You don't need as many of those ancillary roles if people involved actually understand Lean and how to run an SDLC, but in my experience, there are too many devs who don't care about anything other than slinging code and too many managers more interested in expanding their own rice bowls and looking important than in actually streamlining how stuff makes it to prod. And then you need a pile of PMs or Scrum Masters to sort out the mess.