If the insurance companies could arbitrarily raise rates due to a trend that doesn't exist, than they would have already done so. These companies know their margin and they don't bid above that if they want to be competitive.
that assumes that all companies involved aren't doing the same thing. Corporations figured out a long time ago that when one of their competitors does something that makes them more money at the expense of their customers they could start doing the same thing to their own customers and profits increase for everyone without risking prices being driven down by a truly competitive market. The insurance industry in particular is has a long history of shady practices from good old fashioned collusion and price fixing to new techniques like data mining to charge customers different rates depending on where they live, what jobs they have, or how often they're willing to change insurance companies.
In my view, the insurance industry looks competitive, which means that even though these shady practices happen they can't effectively dictate the entire market.
Nope. Because it's flawed reasoning. If many people who get into accidents were driving drunk and everyone who drives drunk buys beer it might seem logical to increase rates for everyone who buys beer, but people who drive drunk are only a small percentage of the people who are beer buyers. That kind of reasoning seems more likely to be a weak justification to raise rates for a large number of people than a reasonable response to a trend.