That's 99% of all used cars on the market

That depends also, many sports cars are far more well maintained than family cars as these cars are often owned by car enthusiast that knows cars, know how to drive them properly and also know what needs to be done to maintain them. The same can't be said for many family car buyers.

Many sports cars tend to be well maintained much of its life. Family cars? Usually maintenance starts going on economy mode after it is 3-4 years old or after warranty.