There is an argument that there's no real evidence that gait analysed - over engineered training shoes - prevent injury. They did studies of this in the US using servicemen who were gait analysed and given a matching running shoe and with other servicement who were just given a neutral training shoe. There was no difference in injury levels between the two groups.
There is also a school of thought that modern (1970s onwards) training shoes that put a wedge of cushioning in the heel alters our bio mechanics, and this causes us to run differently - (heel striking for example) - which can cause injury. Also, the support they provide actually weakens the foot, leading to other injuries. In architecture they always put weight above an arch to make it stronger, they do not support an arch from beneath (like training shoes can do).
I'm transitioning into minamalist training shoes and I can feel the different way I'm forced to run, as opposed to the way I can run with modern training shoes. I also remember joining the army in 1986 and we were issued plimsols (we called 'em 'slaps') and boots to run in. I don't remember having any problems with that.
Personally, I still think running is an art, rather than a science, and I'm wary of believing what the training manufacturers and their funded science reports tell us.
I'm pretty sure that running form is more important than the type of training shoes we wear, but that our training shoes can alter our running form and cause injury.