That's like saying the police shouldn't fire on someone randomly shooting a gun in public. After all, he will run out of bullets eventually, why put more bullets in the air? A car being driven at excessive speed in a reckless manner is a dangerous weapon. If the driver kills himself or any innocents, it is his fault alone. Reckless and wanton disregard for human life, as is the case of those who chose to engage in a high speed flight from authority, is the sign of a shallow and selfish person.
The best option is that no one is injured, an option that is reduced to near nil chance if the police allow a speeding, reckless driver to continue without trying to stop him.
I agree with Anitius Severinus Boethius. This is what the Columbine cops did, wait until everybody who is going to get shot has got shot, then go in and clean up the mess. If the kid was drinking enough to have been stupid enough to lead a 100mph chase, then he was likely to miss a stop light and kill somebody anyway.
If the kid was drunk enough or out of control enough to lead a 100mph chase, then the odds were already high that harm was going to be done. The cops can only shape the situation to 1) limit the damage to the original offender as much as possible, 2) be there to help the innocent.
Aside: It seems the entire concept of innocent vs. guilty has dissappeared. The speeding kid was not an innocent victim.