The personal trainers at my gym do not push their clients whatsoever. It is frustrating to see someone who I know is spending huge money on these sessions and appears to be getting so little out of it. If you ever wanna plays 'spot the personal training student' at my gym just look for the people chatting it up looking like they just walked in the door fresh even after 30 minutes.
I wonder how much of that is the trainer playing up to what the client provides effort wise. A good amount of people who work with trainers are newbies and/or generally not yet in shaped to really be pushed. Those types aren't likely to work with trainers.
People in general respond to the energy they get. I'm not an athlete or in good shape but I've only stopped doing a movement totally and that was because of an injury. My trainer knows I'm going to push to the limit every time and the volume reflects that.
That's just my view from my gym. Most of the trainers there live the lifestyle so I don't think they aren't pushing people for being lazy. No question. That seems to be part of the industry however.