But in 2015 life was good, the housing crisis was mitigated by Obama, and he even won a 2nd term after it, the economy was on the up. Infact, id make the argument things were primed for conservatives by your metric im 2012 not 2016.
The key issues were racial tensions on the rise during Obamas presidency, Sanders benefited from the economic inequality issue mostly, and gun violence was prevelant.
I'd say the trust in government was the biggest factor for Trump, Obama failed on his promises, partly his fault, partly not, and the anti establishment sentiment became too much. Trump was a free speaking no nonsense, swearing, joke cracking wrecking ball of a personality. Grab em by the pussy, hell ye, Mexicans are rapists yee haw!!!!!
He could have easily been stopped though, by not lowering into the gutter, attacking half the country, and most importantly with integrity. Every thing he said and did was twisted into a mistruth, and conservatives were there to show raw footage and context. It baffles me to this day that the media, Hollywood and Democrats still do this knowing it doesnt work, and even if it was effective its too late in the day to do anything now, he's nye on untouchable.
Again, a MAGA friend told me the night of the election last year, that Democrats are going to wish Trump won 2020 when he wins for his 2nd term, because it would have had checks and balances, instead over the 4 years Trump acquired such a base he now he is nearly an despot. Bugger me was he right.