probably half of Sanders voters are there for the taking
the Democratic Party is also full of people who are pissed as holy hell at the political establishment, and Clinton is anathema to them
And that's based on ....what, exactly? From the exit polling, 84% of N.Y Democrat voters either want to continue Obama's policies (52%) or have even more liberal policies (32%). Doesn't leave much room for Republicans.
But even if we assume you're right, Trump had 518,000 fewer votes than Hillary. Half of Bernie's vote total only adds another 380,000 to that.
Trump winning NY is a pipe dream.