>culturally unable to field a competitive on-demand driving service
Or, they could easily decide that that's not their business model. Being a car manufacturer is different from being a fleet operator is different from being a finance company is different from (for that matter) being a car sales and service organization.
A company may decide to do one or more of those connected things and they frequently do in ways that are more direct or less direct. Culture's part of it. But it's also about focusing on capital requirements, core competency, etc.