How about a little OP love for a great question. All the responses saying liability is a large part of insurance cost are correct, but comprehensive is a non-z

How about a little OP love for a great question. All the responses saying liability is a large part of insurance cost are correct, but comprehensive is a non-zero part and your cap in terms of reimbursement does in fact go down over time. There's possibly also a correlation between new cars and accidents (for the same reason sports cars cost more), though this may be somewhat offset by the probability that injuries probably go down as a function of recency of safety technology. TL;DR - there are a lot of factors in costing insurance, but at least one of them should go down in direct proportion to time.