You probably need to consider the wider impact, not just Wisconsin. This was national news (I'm international and I remember reading about it) and would have contributed to his supporters general perception that he was delivering on promises. This isn't really an area where we can single Trump out as he was just being a normal politician here. It's common to announce an amazing deal with a big fanfare which then either fails to materialise, is in fact not as amazing as the headlines claim it to be, or includes previously agreed policies or agreements that are claimed once again as new. This is just typical PR (unfortunately).