Revisiting the topic... I think it would have helped the SNES quite a bit. The SNES was late to the party, but the NES was still very strong when the SNES launched. Nintendo lagged a bit in the 1991 to early 1993 period because the SNES had a much smaller game lineup than the Genesis in those first couple years, adding NES games would have helped a lot.

N64 on the other hand, it was unstoppable for its first year due to Super Mario 64. Backwards compatibility probably wouldn't have mattered much. By the time the PS1 surpassed it in the latter half of 1997, the 16-bit generation was becoming a distant memory.