I know I've used this anecdotal story a few times before, but...
Consumers that aren't of your ultra-hardcore fanboy variety aren't always going to care about the contents of the X360 package, but the price.
When I waited in line 14+hrs for my Xbox 360 on Launch Day (Nov 21st, 05), I was AMAZED that when people were given their tickets, and could chose the Premium, or Core unit, that the core sold out almost as quickly as the premium did! I expected a solid line of premium-buyers, and the late people would get the core units...It wasn't the case. The ratio was around 2.5:1 of Premium to Core buyers....I think 15 of the 20 allotted Cores were sold before the Premiums (30 initial units) sold out.
The Arcade is separating itself from the tard pack image of being an inferior console, since it's being priced at a very competitive price. If anything, Microsoft wants the Arcade SKU to be #1. It always allows them to upsell the accessories at a very nice markup, and most people will get the HDD.
Back from the dead, I'm afraid.