It is too late for Kanye or anyone else to get on the ballot in just a handful of states. He can still run as a 3rd party candidate in more than 40 states. At this point he doesn't need to win. All he has to do is draw a few million votes from Biden, which I think he is capable of doing and his buddy The Donald will get re-elected again.
Bush Sr. lost to Slick Willy in part (mostly?) because Perot syphoned off enough "Anti-Dem" votes from Bush to give Clinton the win. Clinton did not get 50% of the popular vote but managed a majority of electorals.
Hillary still blames Jill Stein (that Russian puppet!!
) for "stealing" votes from her. She still believes there's no way she lost -- someone else has to be responsible for her losing an "un-lose-able" race!
Kanye doesn't often refer to his race. Although many Blacks might identify with him, he's not one to pander based on that alone. Not sure how many Black votes he'll manage to "steal" from Biden -- especially after the lackluster performance of the last Black&White President. Maybe skin color isn't going to be enough to beat the "Not Trump" feelings, and Biden gets those Black's votes anyway.
Hildabeast was supposed to win, therefore many Clinton voters may have stayed home thinking she had it in the bag no matter what. Others who might have voted (D) really didn't like her, so they stayed home. This time, the worst that could happen to Trump (and the nation) is for his supporters to believe he has the election in the bag, too. If his voters stay home, it's the same as voting for Biden by default.
Turn-out will be the deciding factor in a close race. I think the more people Kanye gets to vote who weren't planning to vote anyway, the less it hurts either side. The bigger factor will be if his association with Trump helps, or hurts, his final tally. Either way, a Kanye campaign will keep the press occupied and less focused on Biden, which gives Biden an advantage: less chance people will see his dementia's getting worse.