@engineer,
What you seem to be saying is
there is no point in Democrats reaching out to Trump voters. Correct me if that is not what you are saying. I find that ridiculous.
1. I took a quick look at the polls. There are recent polls, including Pew that say that people would again vote for Trump against Clinton. This doesn't mean that they won't vote for a Democratic candidate against Trump in 2020. It only means they would vote for Hillary Clinton.
2. Other polls suggest people think Trump is doing better than expected. This doesnt mean that people won't vote for a Democratic candidate I. 2020.
3. Trump's approval ratings are still below water. And polling on healthcare significantly favor the Democrats.
4. Polls including Pew also say that many of us reget having voted for Clinton. This suggests that your strategy is even worse.
There is no reason to think that the Democrats can't earn the votes of middle Americans if they sinply treat them with respect.... and every reason to think they will lose if they don't.