Not true. There are a number of "crossbred" cattle breeds, and many have been developed in the US. For example, we raised Beefmaster cattle when I was a kid.
en.wikipedia.org
Brangus is another.
en.wikipedia.org
My dad liked Santa Gertrudis bulls because they threw small calves that were unlikely to cause complications during birth. At least, that was his belief. But, we had beefmaster, charolais, Brahman, Santa Gertrudis, and even a Limousine bull at various times. We slowly moved away from registered cattle, especially when the market turned with the rise of "Angus Brand" cattle. Black skin carries a premium, even at the cattle auction barn- and they don't even need to be Angus breed cattle to be "angus brand" cattle.