I've heard that this type of insurance is expensive and a large part of banks' transaction fees. I can only imagine how expensive an insurance service like that for Bitcoin would be.

However unlike the existing system there will be a transparent, competitive market for such insurance mechanisms, and they will be available to consumers/businesses directly.

I think the banks are pretty focused on offering competitive products that are packaged together neatly to avoid putting too much of burden on consumers (what's the diff between choosing a bank or choosing a private transaction-insurance service?).

I'm paranoid of investment banks but I think plain old banks are benign. You put a certain amount of money in your account and they handle all this for you. There is usually no charge for checking. Credit cards don't charge interest unless you go into debt, etc.

I don't think lack of competition is so much an issue, it seems that the Bitcoin movement just has a fundamental distrust of govt/corporations. I think if Bitcoin money didn't magically appreciate in value so much it wouldn't be much cheaper than banking except for big international money transfers.

Insurance does not eliminate risk from the market.

Market risk is not related to irreversible transactions, at least i don't see how.

What insurance might solve regarding bitcoin irreversible transactions and thieves is that customers of bitcoin services could have their funds reimbursed after a heist.