I know what you mean there. I use all butts when I make fresh breakfast sausage, just made some the other week in fact. It is very lean, IF you compare it to say jimmy dean sausage which is loaded with fat.
When I fry mine up, I cannot set it in the pan and walk away, it will burn as it is "leaner" than store bought. When we cook breakfast on the weekends, I'll cook up one pound of sausage that I made and there will be maybe 1/2 tbl of grease or less in the pan.
But the trade of is, a superior and healthier product that rivals any commercial made sausage.
If you think it is too lean, just start saving any trimmings from ribs and such. In fact, if you eat pork chops, they usually have a fair amount of fat on the edges. I have a nice "collection of fat" just from pork chops that I keep for sausage recipes. We have several butcher shops around here, and no one has pork fat for sale so thats what I have to do.