William, at least when it comes to the PS1, I don´t think luck alone explains the huge success Sony had with it....back then they really seemed to know how to take advantage of Nintendo´s and Sega´s mistakes....I don´t think luck alone would get your system to be the first home console to reach (and pass) the 100 million mark.
That´s the Sony that was nowhere to be seen this gen...while Nintendo´s approach with the Wii really reminds me of their steps with the NES, which is great.