In America, we basically went from the Atari 2600, to the video game crash, to the NES. You're right that the Master System was basically unheard of--to this day, I have a two-second "Master System? Is that what you called the [system I've actually heard of] over in the UK or something?" before I remember that Sega actually tried to have an answer to the NES.
The war was only really on when the Genesis and Game Gear were introduced, and that was primarily a battle of Nintendo's huge opening advantage (Sega more or less had to fight the idea that "video games" and "Nintendo" were interchangeable synonyms after their NES dominance, which is kind of why grandmotherly types still get that confused to this day) versus Sega's sheer unmitigated cheek (with their extremely aggressive Take That-style marketing.)
Edit: And yes, I suppose subjecting myself to Commander Keen is only fair after all my suggestions for you (including at least two more in the works!)
no subject
The war was only really on when the Genesis and Game Gear were introduced, and that was primarily a battle of Nintendo's huge opening advantage (Sega more or less had to fight the idea that "video games" and "Nintendo" were interchangeable synonyms after their NES dominance, which is kind of why grandmotherly types still get that confused to this day) versus Sega's sheer unmitigated cheek (with their extremely aggressive Take That-style marketing.)
Edit: And yes, I suppose subjecting myself to Commander Keen is only fair after all my suggestions for you (including at least two more in the works!)