Most of the people here who you would consider to be on the right probably don't self identify as republicans. I can't speak for all but I can myself. I am not a republican. I feel the party is too concerned with maintaining the status quo and continuing careers, beholden to special interests and the party of democrat lite. I vote for the candidates in any election that most closely aligns with my viewpoints. There are many disenfranchised "republican" voters who feel betrayed by the party that has lost their way and refused to stand up for its principles.
And to your other point
Trump exists beause of obama, and republicans not executing their campaign promises once we elect them. Trump is such an extreme alpha male take no bull **** call it like he sees it persona, that he is a breath of fresh air to many who are sick of Obama's bull **** policies general lack of leadership and indecisiveness and apologizing for America. Trump actively speaks what many in the republican party feel. He is optimistic and wants to make America exceptional. He recognizes there are real threats to america, he values freedom and the 2nd ammendment etc..
There is a reason by and large the GOP establishment and media have turned against him so quickly but voters still flock to him. He is a threat to the status quo and the good ol boy network.
I still don't know if he is my preferred candidate from the right, but I guarantee 100% I would vote for him over anyone the left rolls out without a second of hesitation.