Maybe I was just lucky!
Flying at FL90 or FL100 I spent more than 80% of my time in clear air. Most of the rest I was not suffering icing, maybe 5% of the time. This was commercial charter in an aircraft cleared for moderate icing, so I flew almost regardless of en-route weather and did not work excessively hard to avoid ice. If speed dropped much due to accumulation I never had a problem descending to FL60 or FL70, and usually found all icing cleared.
I do agree with you about flying IFR OUTCAS without radar cover. I have done it many times when no radar service was available. Usually cover is available in places and times that have any amount of traffic, so the statistics are not really surprising.