Radio nav should be taught as much as possible, tracking a beacon or getting a position fix should not be a difficult task in VMC.
However, many training aircraft are not fitted with these instruments, some might only have one functioning VOR with no DME, or the kit might not even be installed, so position fixing is more of a handful. And for an aircraft which is only used for day VFR flying, there is no real incentive to spend the money to get the kit fitted, or fixed when it goes wrong.