I wasn't aware you knew the history. I find it odd, too, but i can think of à reasonable reason for doing this. Good apps without anything to do will not use CPU time, so the only concern is swap space. That, I think, must be the reason for implementing this: on SSD systems, swap space can be scarce (hm, there may even be hardware in the pipeline where it is even scarcer)

I do look forward to a better solution, though. The days of the "Quit" menu item are numbered. Longer term, I think we should get rid of File-Open, too, bring back Lisa-like Stationary documents, and remove File-New.