I very much doubt that most couples that choose not to go with the husbands' names do so just for the hell of it; and I doubt too many marriages take place where the woman makes the decision on her own, without input from her spouse. In fact, precisely because it's still the norm for the couple to use the husband's name, wouldn't it be easier to just go with the flow-- especially for people who don't care?
There would at the very least be inevitable questions from surprised friends, maybe some hurt family members...and then the people who simply need to be told or reminded that the name situation is non-traditional. If people are really making the decision "just because they can," then at the very least they have more work to do than people who choose to use his name. If nothing else, they need to go around saying stuff like, "thanks, we got your invitation, but you addressed it to 'Mr. and Mrs. Smith,' and that's not what we're doing with the names." If this is something that means so little to them, why wouldn't they go the easy route?
I'm not buying this assertion. Could you give some examples of people who choose to reject this long-standing tradition just "because they can," with no reason and without consideration?