I think there's a case to be made for autopilot subscriptions; once autopilot finally does what is says on the tin.

These things require access to accurate and up-to-date road and traffic info, need updates to stay compliant with local regulations, and may (need to) include insurance.

These are all factors that nudge towards a monthly subscription, instead of a one-time purchase. Once the seller goes bust, you wouldn't be able to use your 'purchase' anyhow.