Gravity shares many of the characteristics of Yang-Mills gauge theory. For example, the affine connection plays the similar role as the gauge potential in gauge theory, the Riemann tensor plays the same role as the field strength in gauge theory. And both theories can be well described by Fiber bundle.

I know there is a correspondence between gravity and gauge theory in string theory. But as mentioned above, can't gravity just be a gauge theory itself? The similarity is so strong that I do think gravity emerging from other possibilities is extravagant such as emerging as the requirement of the vanishing of Beta function. Actually, there are indeed some physicists do think that gravity is exactly a gauge theory of Yang-Mills type with gauge group being Poincare group, but it seems that this view is generally neglected by string theorists. Please give me some convincing reasons that this similarity should not be taken seriously. Thanks very much!