Why can't carbon-14 be used to determine the age of fossils that are several hundred thousand years old

 carbon-14 cannot be used to date fossil objects that are several hundredth’s thousands of years, because it half-life is within the range of 50,000 years, therefore another data beyond the 50,000 years cannot be accounted for. Though ages within the ranges of 100,000 years can be dated  though accelerator techniques. Datas as far back as millions of years cannot be accounted using radiocarbon dating techniques.