Could be some other motivation but Insurance is a complex business. There are licenses with state departments of insurance, technology partnerships and then carrier partnerships.

Any carrier with existing strong independent agent channels are going to react to consumer comparison shopping with some caution. Carriers simply aren't going to jump right in bed with Google and put their best sales channel at risk.

As I understood it, Google was also asking for too much. They wanted special treatment and wanted to control much of the consumer experience even after the consumer purchases a policy with a carrier.

Google might have figured out the most lucrative part of the insurance shopping cycle is advertising which carriers can control the experience on without creating a downward spiral on market premiums. Google can easily profit in that space with far lower overhead and less disruption to carriers (i.e. the people who pay Google).