manufacturers selling mining gear to the public.

Assuming SHA-256 is a commodity, that's max 33%

to each maker, plus random buyers into random pools.

Question:  Why does a bitcoin mining hardware manufacturer WANT to sell that equipment?

After all, the theory of transactions is that the seller wants the money more than the product, which the buyer wants the product more than the money.  But if the seller could make just as much money as the buyer does, keeping the machines and running them, why should he want to sell?  

One reason is that the manufacturer might be in an area that has relatively higher electricity costs, and the buyer might be in an area of lower electricity costs.  In that case, there is a reason to transfer the machine to the area with lower cost of operation.

             Jim Bell