they were stupid enough to think that his filthy assholeness wouldn't matter.

It doesn't make them look any better to say they DID vet him. Not one bit.

and they don't have a representative primary system. The winner-take-all in most primary states and the low turnout in caucus states are both a problem. It's very easy to scoop up the delegates in a caucus state with pretty minimal voter participation, but I think the winner-take-all system deserves equal blame here. Trump couldn't have pulled away like that if they'd allocated the primary votes proportionately (and a few people had dropped out earlier).

in Trump's favor?

Yes, apparently that is what I was getting at! Well played!

I fully expect the Powers That Be behind the GOP to revamp their primary system

Everything that the Clinton campaign has dug up on Trump would have been just as readily available to the Republicans if they bothered to do their own homework.

Hillary has run a spectacular ground game. She has people watching Trump like a hawk and jumping on the meat he constantly throws out and turning it into great political ads/videos. Their turn around time just blows me away.

and afraid to have Trump accuse them of their own failings. So they said nothing.

Trump got a lot of attention early for tweeting that Jeb Bush was "low energy" and Bush never recovered from that, and I think a lot of Republicans were afraid of being in Trump's Twitter crosshairs.

centrally involved in the biggest scandal. But even take that away, and there has been so much low hanging fruit, from Howard Stern, to what he said about John McCain, to his financial situation etc., that it smacks of incompetence.

Yup, this is on the 15 other Republicans who competed against Trump. This is also on the RNC and every other non-Trump Republican or Conservative organization.

These fools are so tribal, they're gullible to anybody who claims tribe membership. Trump says he's a conservative, therefore, they think, he is a conservative. Trump says he's a billionaire, therefore, they think, he is a billionaire. Pick anything that conservatives say and you'll find that most conservatives believe it simply because it was said by a conservative. They don't have a single skeptical bone in their body when it comes to evaluating one of their own.

The reality is all the other candidates were more concerned with not alienating Trump's supporters and therefore hung back hoping he'd flame out.

The other problem was that there was no concentrated effort to take him out. If Cruz, Christie, Bush and Rubio (the others were pretenders running for the sole purpose of upping their CPAC speaking fees) had worked together with each attacking Trump on a different weakness they may have been able to take him out. Instead, you had one person attacking him at a time making it easy for Trump to pick off each one.

The entire GOP primary was an example of gross malpractice / incompetence in action.

The GOP owners pretending they vetted Trump is cute. Makes me think of this;

All they had to do was speak to Jeb's cousin.

....to stop Trump. The first was for all the primary candidates to do oppo research on him like you would think anyone with brains would do. The second was the Convention itself.

The first failure was stupidity. The second failure was cowardice. They have no one to blame but themselves. They FAILED.

Teh Donald. No oppo research, never taking him seriously until it was too late, screwing up debates in such a predictable way that it became child's play for Teh Don.

Political malpractice on a scale so YUGE that it may have destroyed the GOP as a functioning party.

Amazing. But, then Teh Donald had a lot of help. The TeaBaggers have done their best to destroy the House, dividing it until it falls. Well, it is now fall, (gawd what a bad pun) and it is more divided than ever.