No, they are not stupid, they are rip-off machines.
I was with the same company for years. Up a few quid each year even down a few quid sometimes. Then one year it went up 70% for no reason. I queried it and they said like it or lump it. Since then I have changed insurer (both on the bike and the car) every year.
Also it is not worth making a claim for a few hundred quid or so as they will rake that back and a load more over the next few years in premiums.