Small costs more
You're overlooking the inherent problems in portable devices. It takes more effort, more advanced technology and more time to produce smaller/lighter devices that consume less power and produces less heat.
That's why PCs have been and will continue to be more powerful for less money. And when I need a PC that I don't intend to carry around with me, I'm going to take the larger, faster, and cheaper one. A docked tablet is just an expensive, underpowered PC.
I also expect all the businesses to buy the cheaper ones for their employees that work at a desk and have no need to carry their work and confidential information around with them.
