Let me throw out a few thoughts and let the experts tell me how I'm wrong.
Often in these threads, someone will comment that the calves from a Longhorn are smaller than those from angus or whatever. To which I often wonder, "No kidding, but how much do your cows eat to get those bigger calves?" You see, people don't really know how much their cows eat. Profit equals revenue minus expenses, but most the focus is on revenue - how big a calf and price at the salebarn.
Kind of like a trucking company that doesn' t know how much fuel their trucks use. You can brag about how much a truck hauls, but if it hauls 20% more, but burns 50% more fuel, is that smart?
If you breed your LH to a heavy muscled bull, and her calf is 20% lighter than a pure angus calf, but she eats 40% less than an angus cow, wouldn't she be a better deal?
Heavier muscled cows eat more. Muscle tissue is more metabolically active, so requires more energy to maintain. Which is why for weight control, you are encouraged to build muscle mass.
The leghorn laying hen is the most efficient, as she has a light body, so energy goes to the egg, not body maintenance. Dairy cows are light muscled so energy goes to the milk.
So every time I see a supposedly beautiful, well muscled cow on here, the first thing I wonder is how much she eats. I saw a beef cow at the fair one year with a nice big butt, and mentioned she was a nice looking cow. The owner said, "Yep, but she sure eats alot!"
So it may well be that an angus or whatever is the better deal, and her genetics for heavier muscling passed to the calf compensate for her increased maintenance over a LH. But without knowing how much a cow eats, I don't know how one can determine that and criticize a LH cow. Just seems like one should get the muscling more from the bull than the cow.
One problem is that breeding two different extremes in muscling will get you calves that are either light or heavy muscled or somewhere in between. Fortunately, consistency is not as important if selling beef directly to consumers.
As this guy explains, we're just now starting to study cow efficiency and feed intake. Amazing!
https://www.youtube.com/watch?v=_6hSQMz8hyo