Hmm, for my €209/year (~$20/mo) liability insurance I get unlimited coverage for personal injuries and €5M coverage for property damage (both mandated by Finnish law).
One major reason is probably that most of the liability portion is going to be covering medical bills in the US. I only did a quick skim of the Wikipedia summary but it looks like Finland, like (almost?) all of Europe wouldn't have that particular liability?
Another reason might be that insurance costs vary widely in the US. I recently had a reason to get an insurance quote in Utah, and it was literally one third the price that I currently pay in California.
All that said, you do seem to enjoy remarkably cheap insurance over there from my perspective. I hardly think those two factors are enough to cover such a large difference.
Medical bills are covered (the Wikipedia summary seems accurate to me: https://en.wikipedia.org/wiki/Vehicle_insurance#Finland). But I'm going to guess that those medical bills, and related damages, are much lower than in the U.S.
Maybe also lower average value of cars and less accidents here plays some part. But not sure how large that difference actually is.
Could also be some difference in the insurance premium systems: The amount of accidents changes one's cost for next year based on fixed rules - the ~$20/mo is with the highest discount (no liability insurance covered accidents in many years). The maximum it can grow to (for me, with my modern car) is ~US$100/mo, by having 4 consecutive covered accidents without accident-free years. Not really sure how wildly this varies in other countries or if the systems are similar...
The optional car insurance is more expensive, my full coverage (including damage, theft, parking, glass, fire, towing, substitute car etc.) is in the ~US$100/mo range, with ~$230 deductible on most coverage, and towing, substitute, glass repair at $0.
Another reason might be that insurance costs vary widely in the US. I recently had a reason to get an insurance quote in Utah, and it was literally one third the price that I currently pay in California.
All that said, you do seem to enjoy remarkably cheap insurance over there from my perspective. I hardly think those two factors are enough to cover such a large difference.