Polling is so odd for Trump: it seems like he is either one of the most electable ones or waaay behind the reat of the pack, but rarely in the middle.
In fairness to Trump, he'd come across especially terrible in Wisconsin with its upper midwestern sensibilities. He also isn't going to be helped by the rather educated Republican base here, especially compared to the rust belt states.
Makes sense. Trump polls much better in Ohio, where the GOP base is more rural and blue collar than Wisconsin, in which the WOW counties have such a huge influence on the state party.