If I'm not mistaken game save hackers are selling NMTs on Ebay. So basically anyone can pay for a few hundred to even a few thousand and the hacker will deliver straight to their town.
Currencies naturally devolve, once all the people with ridiculous sums of tickets have gotten the villagers they want, the market will adjust for people who don't have and or aren't willing to pay thousands of tickets for a villager.
YUP just posted on another thread basically the same thing. Since the game is still new, people are trying to stockpile bells, miles, items, etc. but once they get everything they want, prices will go down (hopefully!)
You couldn't dupe tickets anyway. It only applied to items that could be placed not dropped.
The issue is when duping crowns and royal crowns people had huge amounts of bells and could buy tickets in bulk. Tickets going for 200K bells each is nothing to someone who had 500M+ bells after the first week.