Why did Donald Trump just replace some members of his campaign staff?

From the outside, at least, it appears that Donald Trump has shaken up his campaign staff largely because he felt that they were trying to push him in directions he did not want to go.  He appears to want campaign staff who will be happy to let him simply be himself rather than trying to make him appear to be more “presidential.”
During the primary campaign, Trump succeeded through acting however he felt like acting.  He did not really follow the advice of any political professionals but, instead, said what he wanted to say and did what he wanted to do.  By doing so, Trump defeated all the other Republican candidates fairly easily and became the GOP nominee.
After he became the nominee, many Republican leaders (both in and out of government) expected Trump to “pivot” toward the general election.  They expected him to, as most candidates do, start saying more things to appeal to moderates and to undecided voters.  They expected him to act more like a serious presidential candidate and less like a loose cannon who would say whatever came to mind.  One of the main people who was trying to get Trump to pivot was Paul Manafort.
Today, Manafort has been replaced at the head of Trump’s campaign (he has not been officially replaced, but observers believe that this is the actual effect of Trump’s move) by a man named Stephen Bannon.  Bannon runs a website that has been strongly pro-Trump.  He has urged Trump to stop trying to be “presidential” and to stop doing things to try to cater to moderates and to the people who donate big money to the GOP.  Instead, he wants Trump to be very combative and to continue acting like he did during the primaries.
Observers believe that Trump has made this change because he just wants to behave like he did during the primaries.  He apparently believes that he can win the general election in that way because that is how he won the primaries.  By making this change, he seems to be rejecting the advice of Manafort and other such advisors and going with people who will agree with his own instincts.
https://www.nationalreview.com/corner/breitbartification-trump-complete/