One reason we haven't changed is we frequently encounter low limbs on roads in parts of the country. The Counties etc claim they don't have the money to keep trimmed to the mandatory 15 ft, all the time.
The though just hit of why not a deflector that could catch and deflect the limbs over the top of the antenna. Jack Antennae should have incorporated a sturdy piece in their design on a sturdy base.
Would just have to check whatever is used doesn't interfere with signal.
Might need to be sort of a deflecting cage to keep from grabbing limbs backing up etc.