I only make meatloaf from ground turkey &/or chicken, but regardless, have never been a big fan of regular gravy with it. Depending on the meatloaf "type" (Spanish, Italian, etc.), I usually top with tomato sauce, salsa, barbecue sauce, etc., etc. Although I'm sure a good brand of jarred gravy would be just as nice, especially with mashed potatoes to take up the rest - yum!!
But as far as the drippings? As others have said, I think the fat vs. flavor ratio wouldn't make it worth the effort.