With the first group back in 1980, we played D&D basic for a few sessions. Not sure how many. Maybe 3-4. One player brought the Traveller little black books because he preferred sci-fi and had started reading Fondation. It was cool with us. We created characters, and yes mine died during training. We played one session. The GM told us we would play again soon. Never happened. He tried to design a sci-fi megalopolis from scratch, instead of adventures and only location he needed. Rookie mistake.
We played CoC, Toon and Top Secret. If someone bought an RPG we would try it, when Star Frontiers came out I bought that, since the group already had someone who owned Traveller. When we switched to AD&D something shifted. The group only wanted to play that. Leaving high school for graduate school was also a factor in selecting a single RPG.