Most Thais do not eat beef.
Reminds them of the pet buffalo at home - akin to us eating dogs.
Also, pork and chicken are much cheaper.
None of the Thais that I know here on the island eat beef, and it is only in latter years that the Thai supermarkets have started selling it.
20+ years ago, we could not find beef anywhere on the island.
I would buy it when I did a major shop up in Bangkok.