Yeah, insulator failures are VERY rare, assuming they're installed correctly to begin with.
And, there's the Hadyn Insulator solution -- fail-safe.
One insulator near the top of a shroud or backstay works very well. Have done a number of such installations. This allows you to feed the antenna belowdecks at the chainplate. And, if you're really worried about someone getting a buzz from the antenna/shroud/backstay, put a PVC or plastic boot over the first few feet above the deck.
The one-insulator setup won't work in all cases, though. I just finished an install on a catamaran which had two shrouds on each side -- upper and lower -- which were both attached to a single large chainplate. Had to go with two insulators.