Many physicists believe that there is little possibility of observing extra dimensions at LHC so that some extra dimension models originally designed to solve hierarchy problem (ADD/Randall-Sundrum) will probably be useless for the original purpose.
However some people claim that even if unobserved at LHC, these models will not be forgotten and people will continue to use them for other purposes. I am confused here -- if the proposed model fails to solve the very problem it was supposed to tackle, how can such models still be used? Will these not be inconsistent with nature?
Apart from the confusion, I am interested to know what insight such extra dimension models (RS/ADD) have provided which would be impossible unless such models were developed and studied?