Comparing resting heart rates of different people does not mean a lot as there is so much genetic variation.
It is true that for a given individual the fitter they are then the lower there resting heart rate. However you could take two people who do not exercise, one has resting rate of 75 and the other 55. If they both exercise then there resting rate will drop. The first may drop to 50 and the other 65 but the one with 65 still out performs the other.
Hence comparing resting heart rates between individuals becomes irrelevant. Can still be very useful on an individual bases, especially if you start using heart rate variability to guild tanning.