Another huge difference.
1. Violence might not have been a huge focus, since Mortal Kombat probably wouldn't have come out either. I dare say we might not have had an ESRB if it wasn't for Street Fighter.
2. Tournaments for gaming might not have really materialized.
3. Not to mention the complete change in the gaming landscape, and less of a focus on beat-em-ups and their ilk.
Next question:
What if Nintendo had dropped out of the console biz after the N64?