In June 2020, when this announcement was first made, but before Khan Academy extended the deadline until 2021, the AAMC announced that they'd make the materials available through the AAMC MCAT Prep Hub until the "end of the testing year": .
Then they pivoted to keep it available through Khan Academy until 2021. I'm not in a position to have any insider knowledge about the negotiations, but one hopeful point is that the AAMC is at least aware of how bad this is for students and has explored the technical feasibility of making at least the videos available through the Prep Hub...so there may be a chance that they make a similar decision as the September 2021 deadline approaches? I wouldn't plan on it, but there's at least a shred of hope.