Narrowness of the corridor is a huge factor. You can't pass people as they are lifting their bags or moving slowly. But a wheelchair could go down aisles this

Narrowness of the corridor is a huge factor. You can't pass people as they are lifting their bags or moving slowly. But a wheelchair could go down aisles this wide. And this innovation is really independent of what loading scheme you use. Whoever wants to sit on the middle or aisle seat can wait on the aisle seat before it is moved into its final position before sitting in the seat of their choice.