Marioland sold a lot of gameboys and Tetris was mostly a singleplayer experience.
As a young boy I played Super Mario Bros. on a Nes. I was impressed. I wined to my parents for a NES. The game sold millions of Nes consoles everywhere. I gave nothing about multiplayergames then. It was the sheer fun wich counted.
Oh, and I didn't got a NES from my parents, they bought me a Lynx
All well that ends well