I'll play the devils advocate here;
A lot of fighters fight safe because to them winning or losing is the difference between being fed or being unemployed. When each fighter is on the dockets to be shipped out early in their UFC career after one minor slip up they all train to win to maintain their career. The new up and comers can't take the risks and put it all on the line because they know if they get flash ko'ed in a blaze of glory they won't be cheered for their efforts they'll be fired by their boss so they fight safe, they fight not to lose instead of fighting to win. It's easier to be employed fighting like Fitch than it is to fight like Silva, there is a distinct possibility that the pay structure and ease of which fighters are kicked out creates the boring fights on the undercards because anyone that's not a Jon Jones type (overwhelmingly more skilled and powerful) is going to fight safe to be able to eat. Maybe you won't get that big bonus grinding out a win but not many guys are fired after they win, if any, I can't remember any. When you go for the finish you open yourself up exponentially to counter attacks and if you're sure you can grind your opponent down by training for those grueling slow grappling matches then for some guys it may be advantageous.