Loading times don't factor in at all. The PS1 was the only console where loading times were truly horrendous, and that problem has diminished over the past couple generations. In fact, Nintendo has avoided loading times altogether with the games that they publish, for the most part. I can't complain about a single game that Nintendo has made in regards to loading times.
The two things that truly matter are cost and storage capacity (which modifies cost). In my opinion, I don't see consoles moving back to cartridges ever. Discs were the answer to cartridges, so I don't see how cartridges could be the answer to discs, since we all know they will never be easier to mass-produce, and chances are that they will never have close to the storage capacity.
I think discs will be used for at least two more generations, as I find it hard to believe that people would buy able to withstand downloading a 50 GB game anytime soon, let alone the capacity that will become standard two generations from now.
I find this to be a very interesting topic, but I also think it's funny that people are discussing consoles reverting back to cartridges in the same thread that they are discussing the DS2 possibly moving to discs.
