The iMac is more cost effective by the time you get all the missing pieces. Obviously not a hot seller. Why update something nobody buys? Makes no sense.
Except that a decent monitor is good for 10+ years. My mechanical keyboard can last for decades. No reason to upgrade my Apple trackpad.
Yet through 2012, I bought a mini nearly every other year. Computers get out of date fast, the rest just lasts.
That's why I'll never buy an AIW. Why do I want to keep buying mid-range monitors when I can get a high-end every decade?