I believe the problem of tailwheel insurance in the USA is due in good part to the ever-increasing demise of good, old-school instructors and their ever-twitchier insurance companies. That's what an American, old-school intructor friend told me. There's (allegedly) a proportion of the flying public there that can afford aeroplanes they assume are easy to fly, get a nominal checkout from an hour-building instructor whose experience is severely limited on said aeroplanes, scuttle off to play on the many hard runways over there and....the insurance companies got fed up. Premiums yonder are now well-beyond affordability, especially for the small flight school.
I certainly wouldn't want this unsupported story to reflect on the quality of all hour-building intructors, anywhere, but that's how it was explained to me, when I was lamenting the dearth of rentable taildraggers and it seems credible.
I was taught by said old-school, after getting basics in gliders. I couldn't agree more about the three point landings seen so often: those poor nose-wheels deserve so much better. Tailwheel aeroplanes can be interesting on the ground, but I hope I concentrate just as much in a spamcan. It aint all over until the fat lady's singing, back in the hangar.