RE: artisanal ice cream
If you're paying more than 3 bucks for a single cone, it's artisanal all right.
Seriously, the general difference seems to be that homemade is made from a relatively limited set of ingredients, generally cream, sugar, flavorings/additions, and a simple stabilizer like egg. Plus it's made in a dasher-style freezer that doesn't whip in all that much air.
Grocery store ice cream generally has a much longer list of stabilizers and is made in a continuous freezer that whips in more air. The new "double churned" or "extra churned" lite products seem to have even more air - check the grams per serving and servings per container.