Do you personally plan to spend time trying to reverse-engineer Admiral's insurance model? If not, multiply that by everyone else and you have your answer.
It's less work to just switch insurance companies.
One thing I missed in my point was that many other companies seem to want to exploit (or have already indulged in exploiting) information on social media. This could just be a trigger for other insurance companies to do something similar. Once it becomes somewhat well known, then more people will start curating their social media presence. This curation has already been a big thing on Facebook for other reasons. [1] It's just that the companies may not derive any real value out of such exercises in the long run.
[1]: https://stratechery.com/2016/what-facebook-is-and-isnt/ - this is a great read on this topic of how people present themselves on Facebook