I have noticed a considerable decrease in the number of announcements from just a couple of years ago. Especially on Carnival. And they have not made any announcement in the cabins on the last two cruises either. So they must be listening.
I think if they take the time to print, distribute, collect the cards then they are also taking the time to read them. I think they could be designed better, but I have to assume they paid big money to some research firm to design the cards to give them the feedback they desired.