I think it has more to do with name recognition than anything else. When Joe Piscopo was thinking of running for Governor of NJ, I knew quite a few people who said they'd vote for him even though they didnt know what party he belonged to or his political leanings. Stabenow seems abit anonymous, wouldn't surprise me if her name recognition wasnt all that great for being a two term senator.
She's a three term Senator
Anyway, the GOP deserves to run grifters like Kid Rock instead of impressive veteran candidates like John James at this point