If everything is on the SD card (as in: it won't work w/o the card inserted), then it will have to come with a card pre-installed. In that case, the average user won't even realize there's a removable card. It's turtles all the way down.
The card could come separately from the phone in the same box. Phone boots up off the OS on internal storage, and the intro wizard says "Now insert your SD card, which is where your personal data will be stored." Done.
But if the phone doesn't come with a card pre-installed, people are going to complain that it doesn't work, or that they didn't know they had to purchase a card.
Unless it comes with a card, but the card is not inserted, so the user has to do it before booting up the phone
