The faction you prefer, which saw a role for noblesse oblige and "classical" conservatism, was historically DOA by the time of Bush Sr.'s presidency.
Fair enough, I can still look to the qualities I prefer though. I also will not vote for the wingbats. I liked McCain but with Palin on the ticket I could not vote for him. Enough of the very proud conservatives within the military circles I know absolutely love Trump and what he says and what they think he's doing and having listened to these guys I know there is nothing that will ever get them to change their mind. I'm sure that Trump could go right out and say that he prefers Russia's authoritarian conservatism and wants to make the US more like Russia and he'd get great support.
The era you point toward is exactly when my grandparents had to stop voting Republican. Their [GOP] shift toward favoring southern whites while the democrats took the torch for being social progressives under Kennedy and Johnson reversed the political landscape.

The very best available interpretation of the Republican Party today as a group is that the majority of its voters simply haven't caught up yet because they don't follow current events at all and maintain party-line voting as their primary heuristic.
The SJW association with the Democrats makes them absolutely unappealing to a lot of Trump supporters. They want to to hate who they hate without being told to feel guilty about it, political correctness be damned. Same with the people that see the Republicans as the bastion of conservatism, they'll never vote for another party so long as the Republicans are anti gay marriage, anti abortion, anti immigrant and will vote on the party line every time.

...H-Hillary??
If she wasn't politically toxic with half the country she would have worked (I know she won the popular vote but we don't use that system). Take her policies and have almost any other democrat run with them and they'd probably win. Seeing as she's essentially been running for President since she was first lady she has been far too long in the public eye and is seen as a power hungry expletive. I certainly didn't like her but I'd have preferred her over Trump, I demand at least competence even if I disagree with the policies or individuals.

I wouldn't actually call her strong on defense, she, her husband and Obama were all about the air/drone strike diplomacy. Fine to do a few strikes to make it look like something has happened but never send in ground troops because that's too bloody and messy. She voted for the Iraq war and support the intervention in Libya, that doesn't equal strong on defense, just short sighted.

I think someone like General Clark would do well in a general election for the Democrats over the Republicans in today's environment but he'd have trouble even getting nominated because he's a white male with a military background which means he's not ground breaking enough to excite young democratic voters.