Hacking/Cracking is related to theft. Theft of digital data. So it's obvious that any analogy you make would be somehow related to 'stealing'. Hence you took the most apt explanation.
I can think of only this analogy after a lot of thinking: The students and teachers.
When student are studying in school, or preparing for boards for example. Teachers take a lot of tests before the student gets to take his/her final board exam. Without the constant evaluation of teachers and occasional scoldings from parents, a student would not learn the importance of exam. It takes around a year to prepare students for exams which last only for a couple of weeks. One year of time took to teach (develop) the student and many classroom tests (regression testing / hacking) to find out if students have any weak points (bugs), so that student gets to pass the board exam with flying colors (software reaches in most stable condition).
Ethical point here being teachers are getting paid to teach students and students know they are being evaluated. Similarly a software developer knows that their product is going to be tested/hacked for all sorts of bugs and vulnerability. And just like a student gets to work on his skills again after teachers shared the evaluation, a software developer gets to work to make his product more bug-free after tester/hacker shared their evaluation.
Hoping this analogy makes a little sense.
