Trying to win over Republicans is a bad strategy

Following Gianforte's win I notice a lot of people writing about cuts to social programs like Medicare and how this will hurt Republican voters thus showing how deluded and stupid these voters are. But are less affluent people really voting for the GOP in huge numbers? My understanding is that the GOP's voter base is still more affluent than that of the Democrats and so pointing out the awfulness of GOP economic policy in order to win over Republicans seems like a lost cause to me. Many Republicans probably won't be directly hurt by cuts to Medicare and other social programs and they will be happy to see these cuts happen as long as they get tax cuts. It seems to me that Democrats need to do more to get out the vote among less affluent people who often don't vote as opposed to trying to win over Republicans.