descriptively: Apple has enough market clout so that it (implicitly) thinks developers will pay the time cost to overcome the lack of documentation and save apple the time it would take to write the documentation. The lever isn't good/bad docs, it's the market dominance apple has in controlling access to high-spend customers.

Similarly, MS was notoriously hard to dev on during MS's period of market dominance. It's a lot more dev-friendly now because it doesn't dominate as much anymore.