I have yet to see evidence of Apple 'breaking things left and right'. One notable case: MPlayerX (which still crashes on Mavericks). I don't recall the specific details, but someone looked at the code and found out that its a latent bug in the window initialisation code - it was using size parameters before they were properly initialised. In such cases the values are often
undefined per specification. Incidentally, it worked on previous versions of OS X, but on Mavericks the component initialisation order was changed and the value was zero, which results in division through zero. This is a very nice illustration of a bug in the application code, which does not get detected, because it uses some undefined convention/feature/anything which
by coincidence happens to work. Bugs like these are NOT Apple's fault.
Or if you want a more close to life example - this is like complaining about illegal parking ticket by saying 'but I have parked here for years and never got a ticket!'. Well, it was illegal all the time, just nobody bothered to check it