As long as we have first-past-the-post, winner-take-all elections, it is one's rational self-interest to vote strategically against the party they least want to win, rather than for the party they most want to win.
If people continue to vote strategically like you suggest, what incentive do the politicians have to reform our voting system? I can see it now.
"Mrs. Clinton, I am voting for you solely because your opponent is so terrible. But I warn you, if you don't push hard for some sort of ranked choice voting system in the next election I will....still vote for you because your opponent is still terrible."
Judging from their actions, the Democrats and Republicans would rather lose an election than give people the ability to vote their conscience and case a non-spoiler vote minor parties. In 1992 and 1996 Perot split the vote giving Clinton a win. In 2000, Nader's absence would have likely produced a Gore victory. So both parties have been burned by this, but they aren't exactly lining up to change the system. The duopoly has more benefits for them long-term. They aren't going to do it.
The only way to get it done would be by citizen initiative in the states that allow for it. And even then, both the Democrats and Republicans will come out against it; the law will be easily defeated. We will never be rid of this voting system until it regularly spoils a victory for the same party multiple times and the determine they're better off with it than without it.