you get a discount on insurance

Or, isomorphically, you pay a premium to avoid being tracked.

until they make it mandatory and then the discount will be as good as gone.

The discount is partly there because tracking makes it cheaper for them to insure you, because they can estimate risk better. The better you are at estimating risk, the narrower your margins can be.

Consumers don't win however if they are judged as now higher risk (which should be approximately half of them).

A naive assumption of incentives would make one assume that tracking devices would make people drive safer and save everyone money. More likely consumers will not drive any safer[1] and instead not only have to pay for normal insurance, but also the tracking devices and than data analytics.

[1] Difficulty the incentives people already have to avoid accidents is likely cognitively saturated. See red light cameras.

Consumers on average win, because average rates go down, because insurers have better estimates of risk. Or do you think that the good drivers should subsidize the dangerous ones? (Privacy issues aside.)

I don't agree. The trends of insurers is to cover less and less and to raise their premiums as soon as they can. They are clearly profit maximizers, not "consumer-centric" organizations at all. Just like banks.

Do you want to pay for someone else to be a bad driver? Or should that person put down the beer and the phone?

Insurances should be there to cover risks, and they work because you have sufficient base size to cover for the % of people who will have accidents. Once you start discriminating it destroys the purpose of having an insurance for everyone in the first place.