It shocks me how many people still believe that most cars are pretty much shot once the 100,000km reading shows up on the odometer. Thanks in many ways to emissions laws, today's cars are so much more reliable than their 1970's counterparts, there is literally no comparison. (Emissions laws brought low sulpher gas, cleaner engines, better lubricating oils, etc, etc as well as longer warranties...)
Now, some cars are more troublesome than others. Typically, complexity adds long term operating costs, so if you buy a gadget-laden luxury machine, odds are you will have more long term repairs.
Has anyone really had a car that worn out and truly unreliable at mileages under 200K? Or even 300K? It seems to me that if you buy a brand/model with a good reputation, 300K seems like an easy mark to head to without much trouble. Sure, lemons happen. We've had a couple, and they got ditched early in their lives, but overall, we rarely have a car leave our home with less than 300K on the clock, and below that mileage, most have been solid, reliable vehicles. Our current 01 Forester is often loaded to the roof and used for long trips without a moment's hesitation.
It is true that service costs are more as a vehicle ages. But, there is no savings in buying new. The depreciation expense on pretty much any new vehicle is far, far, more than the service costs on most cars with less than 300K and maintained major parts.