We have switched over to "Fire Stick" flags. They have about a half inch shaft, but also have a spring mount base. They are about $40, but we have three years on 3 of them. The old riprod ones were $20 each and lasted a year or so. The Fire Sticks are a better investment.

 

Now I see why you are having problems, the ones I use are the dune flags, very heavy duty, 1/2 " thick at the base, so breakage is not an issue. I like the suggestion of an old CB antennae and base, spring loaded, and those ant. are tough as nails, just have to find a flag that will hold up, maybe Kevlar !!!!!