As to other reasons apart from the violation of privacy: Every network call adds additional latency and slows down interactions with the OS. Every data gathering feature adds additional complexity to the implementation, takes attention away from other implementation work that could be done instead, and increases the risk of adding further mistakes to the implementation. Personally, I would like OS and application vendors to work on improving security and correctness of their programs and reducing latency instead of adding data gathering features.
> But the line between a necessary network call and an optional one is often blurry.
What would be an example of a necessary network call that an ideal OS (i.e., one that cannot be easily compromised and does not require updates around the clock to correct programming mistakes) has to perform on its own?
If a company is interested in how users use their applications and desperately need our data for it, they may be interested in funding dedicated studies and appropriately compensating users that send their data, if it is so valuable for the company.