I think in years to come people will look back at the fashion for sending cards and be bewildered.
Cards cost £££ for a bit of folded cardboard with someone else's words written inside, and the cost of posting them adds insult to injury. People complain about the cost, yet get (unreasonably, IMO) upset when others don't send them. The talk is often about how people 'can't be bothered' to send cards, but who wants to be a 'bother' to their nearest and dearest? I know people who send Christmas cards to people they haven't spoken to for years - it's a ritual rather than an expression of friendship, yet so many people seem to equate the number of cards they get with how much they are loved.
Sending a text is at least personal, with your own message instead of someone like Patience Strong's, and shows that you are interested in the recipient other than as part of a Christmas chore, yet there are those who see it as 'not bothering' - it's very odd, and it seems (to me) that there is a lot of emotional blackmail around card-sending.
The more 'niche' cards, such as ones wishing good luck for an interview, or congratulations on passing a driving test are at least personal to the recipient and show that the sender knows a bit about their lives, and thinks about them as individuals rather than as someone on a list who might be offended if they didn't send a card.