When I was in nursing school
, the CNAs at the hospital where I did most of my clinical rotations were a lot like the CNAs where you work. They would do vitals at the beginning of, and halfway through the shift, which would take them may an hour each time -- then, for the other 6 hours of their 8 hour shift, they became invisible. In theory they were supposed to help with meals, baths, etc, but good luck actually rounding up a CNA when you needed one.
At the hospital where I got my first job as a nurse, the CNAs were amaaaazing! They were some of the hardest working, most dedicated people I've ever met.
The difference? Management. At the first hospital, management was either oblivious too the CNA problem, or didn't care. At the hospital where I ended up working, God help you if the nurse manager found you doing anything other than working your butt off, and she was around enough and on top of things enough that she knew if people were working hard or not. Slackers were not tolerated.
So, sadly, I'd have to agree with the folks that are telling you to polish up your resume -- and to do your best to find out about the CNA situation at any new position you might consider -- though that might be hard if you don't happen to know anyone who works at the facility. But, I really don't think RNs on their own can turn the CNAs around unless they are backed up by management.