Health insurance is different from most other forms of insurance, though - auto insurance, for example, doesn't pay for oil changes to mitigate the risk of expense of future liability claims.
At least in my country it is very common for auto insurance companies to pay to have windscreen chips repaired, as it's cheaper than waiting for the whole window to fail (possibly causing am accident in the process).
automobile risk avoidance is a lot less complex than health risk avoidance - a lot more people change their own oil than draw their own blood. Also, oil changes would only mitigate the risk of early engine failure which wouldn't be covered by typical policies.
Okay, that was a bad example. I've never carried comprehensive/collision insurance, so I mistakenly thought there was coverage for mechanical failures. As you stated, this is not common.