not sure what event you're thinking of, but Google was a public company before 10 years and they started their first ad program just barely more than a year after forming as a company in 1998.
I consider Google to have been a reasonably benevolent corporate citizen for a good time after they were listed (compare with, say, Microsoft, who were the stereotypical "bad company" throughout the 90s). It was probably around the time of the Google+ failure that things slowly started to go downhill.
[0] a non-profit supposedly acting in the best interests of humanity, though? That's insidious.