It wasn't actually 5 years ago. The things he promised didn't changed now. Personal housing was added in 2014, and was a total mess. And that houses getting destroyed was added in 2015.
That's only 1 and 2 years after he made the promises.
Also yes, people can change what they have said. However, it's bad reputation for Yoshi and SE and the playerbase will lose trust. You can change what you say - but you have to deal with the consquences. And when that means we will still point at that broken promisees years later, then you really messed up with that... but hey, you can change again what you have said ^^