Maybe they thought that the fraud in Detroit was going to be enough to carry that state (kind of like in Los Angeles with CA or Chicago with IL or even Minnesota with Minneapolis/St.Paul).
Prior to the election, I noticed that there were at least two federal raids at union offices in Philadelphia. These offices doubled as democrat campaign offices and were festooned with HRC campaign posters, etc...and it was interesting to watch the clip of detectives wheeling out files, past the HRC signs.
Anyway, I believe that whatever was causing this federal attention in Philadelphia suppressed their ability/will to commit voter fraud there. It may have been what helped push PA over the edge to a red state.
Also some states had new voter ID laws, and some used ‘cross check’ to prevent fraud.
Cumulatively, all of this ate into her voter pool.
Of course that’s why she didn’t campaign in Michigan. She thought she had Detroit well in hand with the fraudulant votes. Another reason she was shocked that she lost Michigan.