If Nintendo continued on with 2D Mario without the existence of 3D Mario, I doubt the series would be where it is now. 3D anything on a console is just the sign of the time then in gaming. That's what created the 3D Mario, and if anything it took the Mario series to a whole different level. Besides, Nintendo would have been criticized by gamers and analysts alike for continuing 2D Mario, for not ever evolving the series. It's nostalgia for a reason. Thanks to 3D Mario. Now seems to be sign of the times to bring back the series to its roots. The different Mario series is actually what makes Nintendo great market strategist. They know how to cater to different tastes of fun.
They also know how to not over saturate the market, not just with Mario but with many of their IPs. That's why I think there will always be a market for Nintendo.
In terms of whether which one is influential, it is probably debatable. What I do disagree about, however, is calling 3D Mario a poison.
