The only way he will lose to Clinton is if Republicans stay home like they did in 2012 … giving us 4 more years of the Obama nightmare.
Trump is not Romney. People like him or hate him but he was not forced on anyone top-down fashion.
Many conservatives stayed home because the GOP forced Romney down their throats. This is not happening (at least not yet) this time around. Now, if they nominate someone like Ryan, then yes you may see another sit-out.
Apparently GOPe did not get the message with the Romney fiasco. They are a rather dense lot.