Nintendo gave home console gaming a good reputation after several years of poor quality, but that poor quality was due in large part to hardware limitations. There's only so much you can do with an Atari 2600. Games could not be very complex, and therefore, were not as fun for the average consumer.
Gaming's growth was inevitable. In other words, where would we be today had Nintendo not shown up when they did? Things would be different, I'm sure, as they have been a trendsetter and a leader this entire time, but realistically, the NES was popular because tech had developed enough to allow for decent games to be developed.
But because Nintendo did show up when they did, you could theoretically say that they "saved gaming", but only with the caveat that gaming would have been saved no matter what.
