Meats with a low fat content, like shrimp and chicken breast are often suggested to be cooked at a high temperature for a short period of time.  However meats with a higher fat content, such as beef brisket and pork ribs, are often to suggested to be cooked low and slow. Oil has a lower specific heat than water which means it heats up faster. Given this, I would expect high fat meats to have shorter cook times. Why is it the reverse? 
The cuts you are talking abut don't just have fat, they have collagen. Collagen requires long cooking in order to be converted to gelatin and stop the meat being tough and chewy, and to add that delicious richness to the cooking liquor and succulence to the meat. 