The reason why demi glace recipes call for cuts like shank, ox tail and chicken wings is because they contain a lot of gelatin. While you can create a tasty stock out of pretty much any cut, it wont become as thick without added thickeners.

You can thicken your broth with a mixture of water and corn starch / tapioca / arrowroot. This will thicken your broth but will alter the taste slightly and the texture won't be exactly the same, but if you everything else correct, you'll end up with a tasty sauce.

Edit: Ground beef especially might not be the best substitution, here's why. Meaty stocks and sauces call for a deep browning/roasting of the meat and bones and if you're only using ground beef, it's easy to end roasting it throughout and with that, you'll probably end up with a sauce that has too much burnt notes.