The biggest problem with SEGA was how to impliment the SEGA CD. We are talking about ROM-chips and not Flash. SEGA did make it possible to combine them into one system, but they literally failed
to consider the fact that Nobody cared at this point in the game and previous titles was unable to work when they solved the problem.

SEGA was beautiful, but Nintendo did it better. Think about it, They were literally converting the Genesis into a Game-Gear for whch the game-gear was the Master-System/Mark III ( Not same ). Nintendo was rocking the Gameboy and the one thing they did wrong was to change the formula ( made the cards smaller ) We could be playing the Gameboy instead of the switch if it was not for that one change.
Even have a full on SNES/Famicom cart converter built inside the switch.