The people who grew up with these games aren't fond of digital-only.
SEGA and Nintendo should just re-release a modernized version of their original hardware (SNES/Genesis/whatever). Give it HDMI out and make it play nicely with modern TV sets. Then, re-release all games on physical format (boxes, full-color manuals, cartridges). They'd make a ton of money from collectors and such at very low production costs. They could sell all of this at very profitable prices. Emulation has no effect on this type of target group. Look at the people buying Evercades.