Ford doesn't have much room to grow because they are a mature company in a mature field. Tesla is creating new fields. Ford doesn't know how to create new fields, therefore they're stuck making small improvements to existing things, and, once someone like Tesla makes it very clear that a new field exists and is viable, Ford will reluctantly follow the market trend.
Ford does normal science [0], Tesla does revolutionary science [1].
Ford does normal science [0], Tesla does revolutionary science [1].
[0] https://en.m.wikipedia.org/wiki/Normal_science [1] https://en.m.wikipedia.org/wiki/The_Structure_of_Scientific_...