Look at it from the POV of the GOP party-leadership:

2016 election.
Our primary has too many candidates, because everybody thinks he knows best.
But it's no big deal: Just as with George W. Bush, John McCain and Mitt Romney, the winner will be someone from the inner circle of the GOP.

Then Trump shows up.
Our voters, who are supposed to root for one of our guys, are rooting for this outsider who has no connections to our party whatsoever.
Come on.
There's no way someone as crass and inexperienced as Trump could wi...
He just won the primary.
The republican voters just picked an outsider over someone from the Republican Party.

Ok.
It's ok.
Calm down.
He has no experience in politics. We can steer him, manipulate him, control him. He needs us.
He can have the photo-ops, we do politics in the backroom and all he has to do is sign whatever we put on his desk.

Yeah, we have won the election. Time to...
Nononononono.
WTF?
He's staffing the White House with his own people.
We need an insider in there, stat! Priebus! We're counting on you!

Now, let's go for the big one first: Obamacare-repeal.
This will be tricky, becau...
Did he just call our bill mean?
Did he really just publicly insult our repeal-bill as "mean"?
Politics is difficult! Sit down, shut up and let us do our work!

Oh, dammit, we're out of ideas for the repeal.
All our ideas suck. Even our own people hate our bills and we have no idea how to make it work.
We should shelve it and move on.
Oh. Great. We lost the Senate-vote.
That sucks, but at least we can now move on to tax-reform.
No, Mr President, we are done with healthcare-reform. We won't do any more suicidal votes!!!!!!

Right.
Now.
Tax-reform.
Guys, we have a full schedule for the rest of the year: We need a debt-ceiling-increase, a budget AND tax-reform.
And we need them before campaign-season 2018 rolls around.
Remember: We'll need something big for the 2018 mid-terms, so...
DID HE JUST MAKE EXCUSES FOR A TORCH-WIELDING, SIEG-HEILING NAZI-MOB WHO KILLED A WOMAN??????