Maybe he wanted to sound self-important and be validated in your/someone's eyes.
I can't know why he would do that, but it is obvious he can't live up to his promises. I have found there are lots of people like that, and I've also been mystified as to what makes them tick. It makes no sense to verbalize something that you can't uphold in actions, so why bother using the extra air? Some people just go about life thinking everyone does that and so it makes it OK for them to do it too, I guess. A friend once told me never to believe anyone ever says, because many people Talk but not many people Do. Until the deal is done, it is not a deal. Sucks, but it has proven to be true in so many cases. I hate to say I've become quite cynical because of it, but there are times when I do let down my guard, I just get the same slap in the face. Think I'd learn my lesson after all these years? Nah.... not all the time...