Regardless of how that one survey was done AS ends up on many best US fiction book lists. The 90s may have also been one of the AS peaks, as I recall being told to read from multiple people (family and teachers). From your own link:
The novel made the New York Public Library’s list of Best Books of the Century in 1996, and Radcliffe Publishing ranked it 92 out of the top 100 novels of the 20th century. In 1999, Atlas Shrugged was number 37 in the list of 100 Favorite Novels of Librarians. A Harris poll placed Atlas Shrugged on America’s Top 10 Favorite Book List in 2008, and The Modern Library ranked it the number one best novel published in the English language in 2009. The novel is listed as number six on Boston Library’s list of 100 Most Influential Books of the Century, and it ranks number five on the list of the 20 Most Inspirational Books ever written. Atlas Shrugged has been translated into 14 languages, including Chinese (2007).
From a story perspective, I found AS too long and preferred The Fountainhead. Were they influential to my younger self? Sure, much like the Bible was to me as an atheist. A story with both good and bad ideas to draw from.