Frankly, a lot of Tea Party folks were very unrealistic about this race.  Any Republican candidate faced an uphill climb, and no unknown stood a chance.  Konetchy, Glenn, and Hekman wouldn't have gotten within 20 points of Stabenow.

The two top Republican candidates were Hoekstra and Clark Durant.  Hoekstra was supported by much of the establishment, including Governor Snyder, and the Yob faction of the state party.  Durant was supported by the anti-Yob faction of the party, and picked up some national conservative support and some Tea Party support after Glenn dropped out.

Hoekstra was attacked as not conservative enough by his primary opponents.  He had certainly cast some bad votes over the years, but this has to be balanced against the fact that he had a 91% lifetime conservative rating from American Conservative Union.  He would have been the most conservative senator from Michigan in a long time, certainly more than James Couzins, Arthur VanderBerg, Charles Potter, Homer Ferguson, Robert Griffin, or Spence Abraham.

Hoekstra won the primary 54-34 over Durant. As in 2006, the primary sapped money and time better spent elsewhere, and created ill will that hampered Hoekstra's chances in the general.

Hoekstra held the safe 2nd congressional district 1992-2010.  He lost the primary for governor in 2010, finishing second.  He announced his candidacy relatively late after having previously declined to run.  He apparently was talked into running, and it seems his heart wasn't really in the race.

Hoekstra's campaign lacked much of a message.  His one big attack against Stabenow was his infamous "China ad", in which a Chinese woman speaking broken English thanks Stabenow for spending so much money that must be borrowed from China.  The ad was attacked as racist, and while that certainly wasn't the intention, it didn't send the message that Hoekstra hoped it would.

After that, Hoekstra dropped in the polls, and fundraising was tough.  Later in the campaign, he ran a couple amusing web ads in which people debate why Stabenow is the worst senator ever.  (In my opinion, she isn't the worst senator Michigan has right now.)

Hoekstra failed to make an effective case against Stabenow.  He had no appeal beyond the Republican base.  In particular, he offered nothing to the white working class voters that Republicans need to win statewide in Michigan.