Having very long hair myself, and having been butchered many times over..... I understand your frustration.
It seems to me that not many hairdressers are good at layering hair that's below the shoulders or near the mid-back length. I don't know if it's not taught enough in class (I know it wasn't in mine, and I learned on the job) that it has to be cut differently than hair at shoulder length, or what the problem is.
BUT I know for my length of hair, from my own experience as a hairdresser, and from my own hairdresser's mouth: hair as long as mine should be cut from the bottom up (sorry if I don't explain well, long time out of the business).
You must NEVER bring hair my length up to the crown because it ends up butchered and looking ridiculous. And it can only be layered so far, otherwise it looks a mess. The shortest layer reaches just below my chin and my longest is at my middle back.
The bottom is the guideline so to speak, and you pull the section outwards at an angle, lifting it upwards until the lowest layer (from the nape) is about to fall loose of the section, then you cut it with the scissors at a vertical angle (does that make sense?).
You can add further layers, by using the shortest piece from the former as your guide, but I'm not sure how on earth I'd explain it without showing you what I mean.
Hope I've made some kind of sense, but in this part of the world, that's what "long layers" mean; that it's layered along the bottom and that the hair is left long and not layered near the crown. Not many hairdressers that I have personally met/worked with can do it 'properly' or well. I say this as a former hairdresser and as a client.