That is a valid concern. I'd like to believe that at some point we will shift back to developing for performance. At home I have been using a 2009 mbp with 4GB

That is a valid concern. I'd like to believe that at some point we will shift back to developing for performance. At home I have been using a 2009 mbp with 4GB of ram and only upgraded it to 8 last year. I have still managed to put an app to the store with it (before the upgrade).