As the better quality dried foods are well balanced and the companies spend ���s formulating them, there is no need to alter the balance by giving anything else. As you say, your cat eats his dry food ok, and if he is healthy why change? I think you might also struggle to get him to eat vegetables on their own!
My dogs have dry food down all the time and they help themselves when they want it. They also get 'leftovers' if I get a takeaway but they are happy and healthy. Yes they would love fresh steak if I gave it to them, but this would upset the balance of their diet and would be unfair as they could not have it all the time. They occasionally get a 'pouch' of meat on their dry food and they don't eat it any quicker than the dry on its own.
I think these TV programmes do more harm than good by making people think theirs are the only ways to do things.
Most of the behavioural problems are caused by the owners not having found out enough about the animals beforehand, and anyone with a modicum of common sense could work out how to correct the behaviour anyway. But that would not make good television, would it?