You sure about that? In my life I've seen Ross Perot mount a successful spoiler campaign, seen Ralph Nader give Florida to Bush, and watched a substantial portion of Utah vote for Evan McMullin. Before my life there was Strom Thurmond and the Dixiecrats, who literally came into being because LBJ argued that blacks were people, too.
The Democrats didn't run Hillary in 2008 because Obama was a better candidate. They ran Hillary in 2016 because their alternative was a literal socialist. If there's one takeaway for the Democratic Party in 2017, it's that they would have been better off running a literal socialist than Hillary Clinton. That's gonna take a while to process but at the end of the day, politicians wanna win.
it's early days. Let's check back in a couple years, shall we?