I'm not sure if awareness of the dangers of UV damage serves an explanation. The area covered isn't huge and tights aren't typical regions for skin cancer. Having said that, the heightened awareness may introduce a cultural bias…
I guess speaking of cultural bias, one other thing to note is that Europe and the US are not the only game in town anymore.
Japan and Korea, and probably in the future China, are big players in cosmetics and fashion these days, and those countries never had a big nudist culture and generally dislike tanning and nudity even more so. And their products are gaining ever greater market share in the West.
