This is my comment to JM's post.
The Jovial Priest said...
Gary Gygax defended the way D&D uses experience points, see AD&D DMG page 85. Heavily paraphrased to be short he said, "In a game certain compromises must be made. It is more "realistic" for clerics to study holy writings to gain experience, fighters to be exercising, magic-users deciphering old scrolls and thieves "casing" various buildings. All very realistic but conducive to non-game boredom."
If the OSR teaches anything it is that rules matter and dictate the tone and the type of game we play.
Horses for courses then.