I want to know the answer to the following question:
What prevented France's 819-line system from achieving the definition it was capable of?
All the background I'm provided with is that "In 1949 France introduced an even higher-resolution standard at 819 lines, a system that should have been high definition even by today's standards, but was monochrome only and the technical limitations of the time prevented it from achieving the definition of which it should have been capable.". Is that enough to answer the question?
Answer: yes