Perhaps they should be querying the quality of their past instruction!
Perhaps. But every instructor has their own habits and own things they like to pass on. Then when you go off flying by yourself, you may pick up your own habits too. Airline Flight Schools tend to be a lot more SOP / procedure based than some PPL schools.
A few hours will show keen interest not just a dream or flight of fancy if you will!
Absolutely!
I'm not against flying privately, especially to work out if it is something for you or not. I'm just saying to give it serious consideration if you don't have spare cash available as it won't give you a massive head start in flying and certainly isn't noticeable in my RHS colleagues once they're flying the line on the Bus.