On the stranger side of things, and to contradict the fact that Nintendo said they aren't bringing in new content updates, Super Mario Run recently got a new 'Friendly Run' mode.
The Friendly Run mode means that you can now compete against your SMR friends without using up any Rally Tickets. Of course, there's a catch. Players with the free version of the game get to race once per day. Those with the premium title get a little more opportunity as you can race a little more - clearing World One means you can race up to three times a day, whilst clearing World Two and above get five races a day.
Much like many online private game-modes, you don't earn anything whilst competing in it. It's quite literally just for fun and bragging rights, but that's okay. It does feel a little like Nintendo's sweetener to pull players back once the game is complete, but whether people dig that kind of thing or not is totally subjective.
I guess we'll have to wait and see if any more content comes to the game, or whether Nintendo's call of 'no content updates ever' was really just a marketing ploy.