Car insurance: Why dont insurers encourage loyalty?

3rd year owning a car in Tokyo, and now moving on to my 3rd insurer. Every year it is exactly the same, the renewal notice comes, and the insurance amount is about 20k higher than the previous year, despite no accidents, no claims or traffic infringements.

Every time, i check kakaku dot com and get more quotes, and receive several offers well under my renewal notice. Why would i stay? it takes 20 minutes to sign up for a new insurer…

I was with Zurich first. When I saw the ridiculous price increase and i called to ask and see if they would offer me a good price to stay on, but no "its because of the welcome bonus"; when actually the price increase was more than that bonus. So much for customer retention… So I moved on to Axa since they offered a good quote and a year later, my renewal notice comes, and as i thought, a price hike from 50k up to 65k. Crazy thing is that while getting other quotes, now Zurich is offering an even better price than i had the first time with them (36k!). In the end I actually chose to go with another insurer, since they let me sign up with my name in english characters, matching my license and registration (Zurich must be all katakana, and i feel this may be a get-out clause for them if i ever need to claim).

So is this just a yearly thing, or is there another reason i am missing for not staying with my insurer every year?

by Tokyo_Dom