Presumably some people's rates also go down on account of more extensive information gathering. If the insurance company just raised rates across the board, they'd no longer be as cost competitive as other insurance providers.
Insurance companies are some of the most regulated industries: their profit margins are capped by law, at least for healthcare insurance.
Ironic that you mention algorithmic renting fixing: a single digit percentage of the rental market actually used RealPage. And when cities banned it, rents were unchanged. The evidence of rent fixing is largely absent.
