I think the market was ready for something new. Sony was a very powerful brand in electronics. Possibly *the most* powerful brand at that time. Sony entering the business finally settled the matter - video games were serious, mainstream tech, and they weren't gonna go away. That cachet would have been hard to beat, regardless of what Nintendo did.
Yeah, no Sony was never the biggest or most powerful brand in electronics not even in Japan Panasonic is still bigger and so is Hitachi.