Where did you read about that life expectancy in Holland Lops?
I haven't seen a reliable breakdown of differences in lifespans. In general, I've hear of smaller breeds living longer than larger breeds, but I don't know whether that generalization reflects the entire community.
I raise Holland Lops, and have bred many does as old as 3-4 and bucks as old as 7-8 years. Those weren't unusual situations. I'd say general lifespan is closer to 8-10 years.