Well, the galaxy is not spinning as you think of it with stars at a constant orbit. What happens is the galaxy's gravitational field is pulling everything towards everything else in the galaxy, very slowly, so it's more like water going down a huge drain, where it circles a few times then goes poof. Same principle with our sun and planets (or your golf ball example), it appears they spin forever at constant distance, but they are slowly being sucked into the sun. So yea the galaxy collapses into the black hole, but the black hole is just a manifestation of the gravity that caused the thing to circle in the first place, and then swallowed it all up so it spins no more. Point is, galaxies are not an eternal event no matter how it plays out, and it must always die and become useless. Where as this thing in the article, possibly does works forever.