I don’t think NES/SNES fans are a major factor. It’s more the Wii fans. It was with the Wii that Nintendo gained a significant female audience, and this has continued with the Switch.
I don't believe this for the Wii. For me most of the sales of the Wii were a fake and illusionnal success thanks to the many women who really believed that they could keep occupied children while losing some weight, or grand parents who saw an opportunity to share video games with children...The core fan base of Nintendo was still decreasing and the WiiU shown us what really was the state of the core fan base. These 100+ millions were not a real market occupation, but just a brillant marketing trick succesfully performed.
(sorry I have only found an old graph)