Not only does it happen all the time, it's often the only way to sort out what legislation means in practice.
A US-centric perspective, stereotypically, would be like 'my Starbucks coffee is too cold, I am suing'. You can have common law without sue-happy individuals.
No, the judges rule with what they have, based on the case’s specifics and the "legislator’s intent" underpinning existing law.
Although it does not become law, their ruling can be used as precedent in later similar cases, until the legislator catches up.
For people, yes. For businesses, absolutely not.
In the EU Apple could have sorted this out with regulators without having to involve lawsuits and legal proceedings.
Unfortunately Apple has a strong deeply held conviction about its walled garden which it’s unwilling to compromise on.
Tim Cook’s hundreds of millions in salary/bonus are dependent on Apple being able to extract a 30% cut out of the entire app and media ecosystem.