First, this doesn't look like a ride-sharing service (and neither does Uber or Lyft, quite frankly); this article depicts Maven as a car-sharing service, similar to Zipcar.

And second, I never said anything about legal issues. I don't see a legal issue or requirement against vertical integration. I simply wondered whether this might create a set of incentives that don't align with what consumers want. That wasn't meant as a suggestion to prevent that through regulation.

To actually say something about legal issues directly: while I don't particularly want to see regulation in either area, I see far fewer ethical issues with regulations attempting to protect people and encourage the construction of better services that people want, and far more ethical issues with laws protecting existing services from competition by people trying to build better services. The former regulations at least try to benefit people; the latter benefit the specific protected companies. And I consider it perfectly reasonable to evaluate ethics as orthogonal to current law.