Plenty of plumbers and electricians get 300k+ out of 80s and 90s E-series vans driving exactly how you described. Cops and taxis get 300k+ out of the frequently driving like you described.
You can also have a pretty crapped up engine well before 100k if you only ever drive to bingo, church and the grocery store.
Once you start looking at the details rules of thumb like $roadmiles = $trackmiles * $x usually can't be applied to complex systems with lots of variables with reasonable precision no matter how much time you spend arguing about x
Yea, it depends. All my argument was saying is that even in the most reliable, conservative race cars I've had experience with, which used a Mazda truck engine which was pretty much stock, they were not lasting anywhere near 1/3 miles. 1/30 of the miles would put you at 10,000 miles which is probably closer.
Any raspy, high revving motor that needs RPMs to make power is going to last even less. Start modding and using race-purpose engines and it's even less still.
Edit: are you sure a lot of police cars are getting 300k in that kind of driving? I don't think all cops drive like that most of the time. I'm very skeptical of that claim you're making. I'd imagine most cop cars are retired around 100k which is what a quick Google search shows some agreement for.
You can also have a pretty crapped up engine well before 100k if you only ever drive to bingo, church and the grocery store.
Once you start looking at the details rules of thumb like $roadmiles = $trackmiles * $x usually can't be applied to complex systems with lots of variables with reasonable precision no matter how much time you spend arguing about x