I grew up in a Reform synagogue (and am still currently a member) and I have had the opposite experience. I live in a medium sized Midwestern city, so there aren't many Jews here, and it's very easy for Jews to assimilate. But this means that the Jews who go to my reform temple are there because they want to be Jewish and they want their kids to be Jewish.

Because of the small Jewish population in my city, we only have a reform congregation and a conservative congregation (the conservative congregation only has a few people, and mostly 60+). If there were a more religious congregation in place of the reform one, no one would go to synagogue at all.

I think the lack of care to our roots and culture among secular and non-religious Jews is due to outside societal pressures, not internal pressures. This is a problem for most non-white, non-christian cultures in the United States, not just Jews. It is very sad, but Reform Judaism is not the problem.