The only drug that springs to mind as made for the sake of being a safer alternative to a street drug is MXE, which according to wiki was actually invented for grey market distribution, with the specific goal of being less damaging to the urinary system than K is. In general though, the approach to RCs is to find whatever minimal modification to a current drug makes it able to skate past the current state of the law, with a secondary consideration to making sure it actually works. Indeed, most RCs are less effective than the street drugs they're knocking off, with the notable exception of the NBOMe's, although as a tangent, they are horribly less safe than LSD, which alongside weed is probably one of the safest drugs around in terms of therapeutic index.
I'd definitely side with consumer here, greed is the motivator, not any sort of utopian view towards creating safer drugs. I believe NZ did have a proposed law at some point to allow legalised NPS's after their safety was proved in a proper clinical trial, but IIRC that didn't make it through parliament.