Taken from a Telegraph article: "Their growth reflects a rapid shift in attitudes towards religion in America among young people, with one recent Pew poll finding that more than one third of Americans aged 18 to 29 now say they have “no religious affiliation”, compared with less than 10 per cent of their grandparents’ generation."
That's a significant growth trend over a reasonable time period.
"What this means for American 30 years from now is unclear, admitted Dan Linford, the president of the Virginia Tech freethinkers and a graduate student in the philosophy of religion, but he believes that gradual trend towards more openness about religious non-belief will bring social change, just as it has for gays and lesbians.“At present the Religious Right has a tremendous amount of power, but they are getting older,” he said. “Surveys show young Americans are rejecting institutional religion because they identify it with the Religious Right and values that they find off-putting, and frankly, immoral.”
Other studies have argued that the polarisation of American politics has turned off many young people from institutional religion since Republicans, who fare poorly among young voters, have been conflated with religious groups considered “judgmental, homophobic, hypocritical, and too political”.
Interesting quotes again. This is just one article but there are many. Have a rummage and see. I don't discount what you say about the rise of Islam globally, but in the west the trend among YOUNG people is the one of no religious affiliation.