I'm pretty sure it'll still stay open since not everyone's willing to go through the hassle of buying amiibo cards. I honestly don't think it's going anywhere. The Post Office forum will most likely get an increase in activity.
I think it will die down a bit more, but not everyone will have the means to buy the cards and I think if anything it'll make the post office busier because people will be trading villagers that way more.
Yeah I think it will stay somewhat alive, unless people actually manage to get the 10 cards/villagers and stuff they want. But yeah the update is a bit killing the idea with campsite though.
We have no intentions of closing the board, if that is what you are asking. Even though it'll be easier to acquire villagers not everyone is going to want to spend lots of money on cards.
Well it's already really quietened down the last few weeks, which is why I stopped cycling. But really, we can't all get any villagers anytime we want even with the update, since to do that you would have to have a full collection of all villager cards which isn't cheap. I've bought 3 packs up to now and have some repeats already. The plaza might even pick up a little with the new villagers, and villagers may become easier to find if you can get to somebody who has the card you're needing. Don't think it will die completely but who knows
I think the Villager Trade Plaza will still be useful to get villagers you don't have the cards of. I know I don't have all the cards of my dreamies, so I'll still be using it.