That is one way of looking at it, but nothing is ever so simple, there are so many other factors to consider, what about reaction speeds of a driver? The driver in the car with expensive tyres could be slower to react, or they could have worn out brakes that don't respond as well or the tyres. What about a driver who has the best tyres but drives recklessly, should they get a lower premium purely cos they have better tyres and hence insurers making a false judgment that his less likely to have an accident. It is way too complicated and IMO pointless. To me it all comes down to driving sensibly and fate, the latter you can't do anything about.
Uh-oh. We've got someone who doesn't understand probabilities.
Let's do some maths with some imaginary figures, considering only two possible variables (massive oversimplification).
Rubbish tyres give a risk of 0.6, good tyres give a risk of 0.9.
This is based entirely on tyre performance, stopping distance etc, and not on how rubbish the driver is.
Reckless driver gives a risk of 0.2, good driver gives a risk of 0.9.
So, reckless driver but good tyres gives a risk of 0.2*0.9 = 0.18.
Good driver but rubbish tyres gives a risk of 0.9*0.6 = 0.54.
But, good driver with good tyres gives a risk of 0.9*0.9 = 0.81.
Your argument seems to be that the reckless driver may have good tyres and the safe driver may have rubbish tyres and zomg not fair premiums.
But you're looking at one specific example whereas the insurance companies are looking at thousands, and,
on average, those with good tyres are less likely to have accidents
because they can avoid collisions better regardless of whether there's a few muppets with good tyres (as there will be with rubbish tyres).
And the good driver can reduce his premium further by getting better tyres, which reduce his chance of having a crash.
It's not rocket science that if you do something to reduce your risk, you should pay lower premiums - and there can simply be no denying that person x putting better tyres on his car will reduce his chance of a crash, all other variables staying the same.
Rubbish drivers tend to have crashes which would raise their risk profile far more than someone putting linglongs on a banger.