These incidents seem really rare, I definitely would'nt bother with any insurance as its in the really remote places you want help, but that's exactly where help would be least likely to arrive quickly.
Its only happened to me once. I had a collapsed rear wheel once while riding in Mid Wales, no chance of repairing it so it was a call for help job. Problem was the area I was in had no mobile reception, so I walked a couple of miles to the next village and found a phone box, but it had been vandalised and was'nt working, so I had to walk a few miles to the next village. When this second phone box was also vandalised and unusable I could'nt be arsed with walking any further in silly SPD-SL shoes, so I went and knocked on the door of the village pub, which was shut, and told the owner my tale of woe. The owner told me he used to have a Campagnolo equipped bike years ago, and was delighted to see I had one too. The owner opened up and let me in, let me use his landline to call for rescue, and then served me a drink and made me a sandwich. People are generally really helpful so don't be afraid to ask.
It also made me fall out of love with fancy wheels with aero bladed spokes, especially while out riding in the shires. I'd broken 5 spokes on my rear wheel but nowhere in a 60 mile radius had any replacements, they were a special order which would take days to arrive, so the rest of my long weekend cycling in Wales involved no cycling at all.