The math changes in every State. To assume that all breaks for the Democrats is preposterous. Particularly if Hillary gets indicted. Trump also changes finances. Trump would run way better than other Republicans for example in New York. I doubt he wins there, but he could make Hillary spend there to defend it and he's not limited in spending like she is
If Hillary is indicted, that's a game-changer.
But thus far, Clinton is leading Trump by 25% in New York, which isn't much better than other past Republican candidates.
And the math doesn't change in every state. Most states aren't going to switch.
The reason why the Republican establishment is shitting themselves over Trump is because they think Trump could lead the GOP to a Goldwater-type disaster and consign the national party to the same state as the Republican party in California. They see polls like this one and in Arizona.