All these things are to try to keep the car in the dealer network. It is short-sighted and manufacturers keep trying. There's been a cycle of this for many years. There was a move to keep all repair procedures and servicing data secret, until the EU stepped in and made them legally obliged to make it available. That was a long time ago.
As cars get older, repairs are more expensive as a proportion of the car's value. Smaller garages help prolong the car's life by repairing it cheaper. This keeps the cars going longer, and helps maintain their resale value, so reducing the depreciation slope. Making it difficult to service in later years eventually causes higher depreciation. Some manufacturers see this and make it easy to service in later years. Seen this cycle many times over the years.
Smaller garages are often better at diagnosing and rectifying faults, especially in popular models, as they see the older cars. Dealers only see newer lower mileage ones, so don't see the faults, so are less able to diagnose and repair. As an example, see how many times on this forum answers are presented where garages have failed.