In 2012, Mitt Romney won 51% of voters with a college degree (no postgrad), 53% of married women, & won white women 56-42, widest margin of any candidate since Reagan in 84. Driving those voters off is a choice.
Of course, anything that changes course to add to your political coalition will cost you *some* voters, but a winning strategy builds out from the people you have; it doesn't burn it down in hopes of starting over.
Really only successful example of a party rebooting itself by abandoning its base's concerns to chase new voters was Democrats in 1928 after 1920 & 1924 catastrophes. Ds lost badly in 1928, but set themselves up for explosive growth in 1932-36...with huge assist from Depression.
It's debatable historically whether, without the Depression, the socially conservative white southerners who'd been the Dems' bedrock thru 1924 would have jumped ship earlier at the party's abrupt shift to an urban, ethnic Northern constituency.
That said, FDR managed the balancing act better than Al Smith had; he wasn't Catholic, Prohibition had burned out as an issue, & FDR played up Southern ties, was more openly friendly to segregationists.
(Aside: anybody who talks about Richard Nixon having a "Southern Strategy" & doesn't acknowledge FDR's Southern Strategy is either ignorant or selling you propaganda.)
Anyway, here is the shift in the two-party vote from 1924 to 1928, by state. Massive Dem gains in a whole bunch of states they still lost, but that made them competitive again (states in purple flipped R to D): 
Real talk: Bush in 2004 & Obama in 2008 & 2012 won popular majorities. Everybody else the past 30 years - Trump, Hillary & Bill Clinton, Romney, Gore, McCain, Kerry, Dole, W in 2000, HW in 1992 - was at the mercy of fate.
