> The big problem seemed to be competition. You only get to write the insurance if you're the best price but the best price is not necessarily one that makes sense for the business.

That's straightforward - your insurance product needs reputation. Sure you could go with "that other guy" but we're Lloyd's! You know we'll pay out if it's a legit prize winning.

Also marketing - lowballer needs to spend to get visibility that would cut into margins. The market player that has the most data knows exactly how much to spend on marketing and how much to charge in premiums.