Yep, you've nailed it. You clearly have experienced the same as my OH. He has a little black book of names and direct line phone numbers after being on chemo for five years and every sodding month there's some cock up or another that he has to sort out as no staff are remotely interested. He'd be dead if he wasn't on top of it himself.
As for the departments not talking to eachother, another yes! When he was first diagnosed, he had all kinds of tests, bone marrow, skeletal x-rays, MRI and CT scans, etc. They referred him to a different hospital in the next town, and the consultant there glibly ordered the whole lot again, same NHS trust, same county, but apparently "he wanted his own" and wouldn't wait for them to come through from the first hospital. (I can only assume he wasn't confident they'd ever appear after all his referral "file" was a single typed A4 sheet with no test results, just a generic, "this patient is xyz, please could you review" or something similar - how hard would it have been to ping over some actual detail???
Over the past five years, he's had other issues, i.e. a broken foot and a need for dental treatment. No one gives any real information - the oncologist glibly says ask the dentist, the dentist says ask your oncologist, he's constantly left in limbo trying to actually get advice/direction as he's just fobbed off.
Even with things like iron deficiencies that pop up on oncology blood tests, the oncologist won't just issue a prescription or give the data to the GP to issue, OH has to get a GP appointment, then a GP blood test, then the GP will say something like "not low enough to prescribe", so he tells the oncologist who says it IS too low due to the chemo effects, and back he has to go to the GP to tell them, and they then very reluctantly agree to issue the iron supplements. It's all so time wasting and maddening that they just won't communicate directly with eachother and leave the patient as piggy in the middle, which means more appointments, delays etc all wasting NHS time as well as his own.