In 2004, “Michigan was won by Democratic nominee John Kerry by a 3.4% margin of victory. Although no Republican carried this state in a presidential election since Bush’s father George H. W. Bush in 1988, early polling showed the race was a toss-up, thus was considered as a possible target for the Republicans.”

en.wikipedia.org/…/2004_United_States_presidentia…

In 2008, “Michigan was won by Democratic nominee Barack Obama by a 16.4% margin of victory.”

en.wikipedia.org/…/2008_United_States_presidentia…

in 2012, “Michigan was won by Democrat Barack Obama with 54.21% of the vote to Romney’s 44.71%,”

en.wikipedia.org/…/2012_United_States_presidentia…

In 1988 Michigan went Republican and then up until 2012, went Democrat.

In 2016 it went to Donald Trump. A state that hadn’t voted for a Republican President since the last century changed.

Then in 2020 it went back to blue side.

TL;DR: in 9 elections, Michigan only voted for a Republican president twice. '88 = Red, '92 = Blue, '96 = Blue, '00 = Blue, '04 = Blue, '08 = Blue, '12 = Blue, '16 = Red, '20 =Blue. This isn’t a highly unusual pattern. If anything, it was highly unusual and showed the appeal of former president Donald Trump to flip the blue state red in '16.