You can make satisfactory beer from a can, if that's good for you.
I love food, so I always have my "spaghetti analogies".
In this case, say you want some spaghetti. You could buy a can of Hunt's Spaghetti Sauce, and have possibly decent spaghetti tonight, if you don't mind the Hunt's sauce. (Canned beer kits).
If you want to spend a bit more time, you could open up a jar of Ragu and add some homemade meatballs. (Fresh extract with steeping grains).
For a bit more work, you could buy some tomato sauce, fresh herbs and tomato paste and make your own sauce. (Partial mash brewing).
If you want to gourmet out, buy a bushel of tomatoes and fresh herbs and have at it! (All-grain brewing).
I've actually been happy at times with Ragu, but prefer making my own sauce from fresh tomatoes. The same is true with beer. You can make beer out of a canned prehopped LME no boil kit, and be perfectly content with "good enough" beer. Lots of people are, and that's fine. Or, you could go crazy and strive to make a "craft" beer. That's fine too. There is room for everybody in brewing!