It was only a matter of time before a Sonic commission came up. To reminisce how big Sega was back in the day is kind of hilarious. They caused so much havoc in the balance of power that no one had been able to do before. That five-year triumph period alone is enough to cement them in video game history. And it was all arguably a fluke, because even when they were on top they were making outrageously stupid decisions.
While they've had some financial success since then, quality-wise they've been all over the board (mostly on the crappy side). Sonic is a video game icon, though, and his image has allowed Sega to continue to root itself in the minds of players everywhere (for better or for worse).