Exactly...marketing and something easy to "brand"....Black is easy to see, and breed for. Cattle breeds go in cycles. Since you are in south Texas, and I have raised cattle for years in Texas...below are a few of my observations and opinions...and observations.
All beef cattle eat about the same, given the same feed program to slaughter.
Black hides can be put on calves with bulls from Angus, Maine Anjou, Brangus, Spanish fighting cattle, Holstein, and many, many others. The Angus breed association capitalized on their color and that of many other breeds.
The best cow and bull is the one that works for you and fits your operation...regardless of breed.
Beefmasters, which I raise, have six criteria for breeding selection: disposition, weight gain, fertility, hardiness, milking ability and conformation for cutability.
Color and horns are not a Beefmaster criteria. You can't eat the horns or hide. Breeding for only one characteristic makes fast progress in that direction for a breed while allowing many problems to develop in the breed. Examples, not expressed in every individual, include:
Hereford...pink eye, tropical decline, heat sensitivity, dwarfism, insect susceptibility
Angus...temperament can lead to going thru fences, insect susceptibility
polled gene is linked to lazy prepuse in bulls and injury from stepping on
long horn...lack of meat conformation, slow weight gain
Charolais...large birth weight calves, calving problems, slow breeding
many other examples exist for other breeds as well
The Angus breed focuses on color and marketing while the cow/calf producer has to focus on a live calf, gentle cattle he can pen and handle, weight gain at sale time, a calf every 12 months from a cow, avoid vet bills and insect problems, and good meat conformation at sale time.
True story...my neighbor was raising black baldies...mix of Hereford and Angus...he had to have vet come and dig ticks out from all the ears of his cattle...so many they were falling down the ear canal, festering and causing infections, cattle staggering around. Vet visited next day to give my heifers their brucelosis vaccination (mandatory at the time) and looked in ears and all over my cattle. We found one tick crawling, not stuck, on one of my heifers. Conclusion, Beefmasters have a natural insect resistance as a result of their hardiness selection criteria.
That said, everybody defends their favorite breed...use what works for you...but select individuals which fit your climate and terrain and management skills. I put disposition as the first criteria, if you can't load it into a trailer from your pens, you can't even sell the animal.
Marketing. Marketing. Marketing. The first requirement for "Certified Angus" is the beef has to come from a carcass with 51% black hide. Purebred Angus are all black.