Frankly, it's not difficult for ranchers and beef companies to test their beef. It costs only a few more cents per pound. Some companies, in fact, volunteered to test, only to be stopped by the USDA. Of course, a few more cents per pound results in millions to billions of dollars of lost profit, according to big corporations' calculations. However, I'm sure that most consumers would gladly pay a few more cents per pound in order to eat safer beef, if these companies would simply pass on the costs to the consumer. They do it all the time with taxes!
Unfortunately, the beef industry is incredibly politically powerful, even since the 1800s. They've been getting subsidies for a long, long time. Yes, you heard right—your very own tax dollars are supporting our massive beef industry. (I'm sure vegetarians and vegans reading this are already grinding their teeth.) So I'm quite cynical as to how well we can rely on the government for a solution to this.
Mad Cow Disease (Creutzfeldt-Jakob Disease) works very very slowly in human beings. It can be up to 30 years after initial infection before the disease manifests itself. There's also some evidence that suggests that a lot of these cases are misdiagnosed as Alzheimer's or dementia, which is frightening—we may have an emerging epidemic in 30 years with thousands or even millions of people literally losing their minds.