I'd agree with that. I got my M2 when I was 18 and am 35 now with continuous insurance the entire time. Even when I moved out of the country for 6 months, I kept fire and theft on the bike to make sure my coverage was continuous. I'm now seeing probably the lowest rates you can which has allowed me to insure two high CC bikes, but even with two on the road I'd find it hard to justify paying much over $2000/yr combined. I'd tap out at $2500 but am already borderline considering taking one of them off the road and I'm not even there yet. Even at my rates it is still way more than we should be paying.
I just spoke with someone who used to ride an R1. He took the insurance off for a few years with his growing family and now because of that (despite being over 40 now), his rates are way high, too high to get back into it. He regrets taking off the insurance for what he thought would be a temporary period of time.