Google could provide (paid) update services for handset makers or carriers. The incentive for those to pay for this service would be that those devices would be

Google could provide (paid) update services for handset makers or carriers. The incentive for those to pay for this service would be that those devices would be much more attractive for customers. As a consumer I would be willing to pay more for a phone if I could be sure to get updates for 3 years ASAP.