" ... that most people will not spend 50%+ of the cost of the Pi on a box?"
Good point - that's why I use a cheap PAYG mobile phone.
I am amazed at how much money people spend on mobile phones just to make phone calls or to send texts. Of course, they justify the cost with other things - primarily associated with social networking - after all, apparently there is no more fun to be had in the world than by taking photos of you and your mates when you are all paralytically drunk on a Friday night.
I have the same thing with tablets - people spend more than the price of a PC, and twice the price of a netbook, on something that doesn't even have a keyboard and can't run the software I write myself unless I give money to Apple and others.
People are free to spend or not spend their money - on smartphones and fondle slabs if that's what they want.
Some people look at it a different way. They save so much by buying the RPi that they can afford to splash out a bit more on a case.
Let's be brutally honest, price is the RPi's single greatest USP - pico and mini ITX boards can do far more but cost more. I just checked - the Asus C60M1-I AMD Fusion Mini-ITX Motherboard is 69.00 GBP at http://www.mini-itx.com/store/?c=65
and you can have as much RAM as you can eat - and a wide choice of cases from about 30.00 GBP upwards (http://www.mini-itx.com/store/?c=3#C294
No, I have no connection with anyone who sells mini-ITX stuff, or anything for them, but I do use a couple for dedicated tasks - like driving a 3-axis CNC milling machine and manufacture/calibration of products.
The RPI would be great for such tasks - all I have to do is convert the software I have written from Windows to Linux. Let me do the sums. A mini-ITX board would set me back an extra 45.00 GBP and programming time comes in at about 25.00 GBP an hour - a no-brainer really.
Life's single regret: not patenting dongles when we invented and named them to protect the Wordcraft word processor on the Commodore PET!
You can buy 31 RPi3s for the £639 price of one Samsung Galaxy S7 Edge smart phone - who buys this stuff?