It's called Primary fatigue. Most Republicans want to move on to attacking Obama, tired of attacking one another.
Most of those you listed said they wouldn't endorse a specific candidate in the primary because they would in the end support whoever the actual nominee is, even Romney. You have to listen closely and not filter what you hear with what you want to hear.
Palin long ago and more than once said she would support Romney if he was the nominee. Yes there was a bunch of mythology created about her that she would slay the establishment candidate (Romney) and then go on to beat Obama in the debates. That was great $$$$$ business. Then when she admitted she wasn't running a smaller myth was created by Newt (encouraged by Palin) that he was that one, He told us many times he couldnt lose the nomination but he looks like he is, and badly too. He is a long time book-speech seller master and he taught her how to do it.
Even if Romney gets beat by Obama they have to be seen as opposing Obama in it, no matter what they think.
“Then when she admitted she wasn’t running a smaller myth was created by Newt (encouraged by Palin) that he was that one”
Newt didn’t “create a myth”. If you recall, Todd Palin called him to say he was endorsing him (TP even talked about it afterward). It was widely presumed that, considering Sarah’s such a public figure and their marriage is a close one, he didn’t do this without discussing it with her first. She also spoke out in support of Newt not long after, and although not Formally or Officially endorsing anyone as her husband did, many (including myself) looked at it as a clever way to endorse Newt via Todd without publicly boxing herself in.