That's a terrible comparison. Destiny is an MMO, where the multiplayer is the main selling point of the game. Crackdown is a primarily singleplayer experience with co-op as an extra feature.
When did Destiny become an MMO? It's an online game with MMO trappings - mainly the negatives like grinding and rare drops - but it's missing that first M entirely as there's nothing massive about it.
There's really no reason that Destiny had to be online-only. The single player portion, bad as it was, could have been done offline.