I think there are 3 reasons
Training, I can make a fine pastry. To make the kind of pastry that haute cuisine requires with equal amounts of fat & flour takes me hours. Rolling & wrapping meat/fish/veggies into clingfilm logs goes wrong more often than it goes right and well its going to be quite some time before I get the hang of quenelles. I've got a job and a social life that isn't all cooking & cocktails, so I don't have the time to practice, which brings me to ethos.
Ethos. I'm a cook, I want most of my food out on the plate & eaten. I'm not always prepared to cut & chuck good food in order to make a better looking dish. I'm cooking for 2-6 people not a full service 2-3 times a day. I'm cooking for fun (or hunger) not for a living. I'm coming from a completely different place, a different starting point & pretty much ending in a different place.
Ethos is the big difference, I can't really make the investment required to turn out one plate of star grade food. I don't have the time to practice that one dish over & over till it's perfect. And frankly I'm not great at cleaning ovens, fridges & so on, sure its all hygienic but its not enough to coax the constant & consistent performance from my kit.
One day I might by luck & skill combined turn out that plate, but I'm not counting on it. It's not going to stop me buying serious cookery books & attempting the recipes though. I'll just try to be a little less harsh on myself when it doesn't come out exactly as it might at a restaurant.