Why is the trend these days to take the husband's name? I cringe every time someone on my Facebook's feed has all of a sudden changed their last name. And if I were to ever bitch and moan about it, they would probably say it was their choice blah blah blah. Very well then, but the tradition is directly descended from when women were the property of men. Who wants to be associated with that tradition? Well, most women these days, inadvertently.
Classic Atlas fallacy. People don't think about the historical context behind these things.
As for the trend towards changing names, I'll offer a couple hypotheses.
1) Marriage rates are declining. The people getting married in 2014 are somewhat more conservative in aggregate than the people getting married in 1985.
2) There's a negative stereotype of women who hyphenate their names, and people don't want to be associated with that.