Very well then. I will probably miss a few things until asked. So feel free...
Just from a technical point of view for now.
I am gonna number bullet this :
How the GPU industry works :
1. The GPU or chip :
This is the internal brain of the graphics card that is VERY similar in many ways to a CPU. most notably the differences that most people can understand is core count. Think of the GPU as many tiny single cores that work separately on different parts of the image that you see on your monitor.
Here is a video that outlines the making of a silicon wafer (multiple chips) at Globalfoundries, they make all AMD chips.
http://www.youtube.com/watch?v=qm67wbB5GmI
This process takes up to a month for CPUs, newer tech has dropped that time, but not by much.
2. The board partners or manufacturers :
These include companies like Asus, MSI, XFX, Sapphire and many more.
These companies basically make a deal with AMD for the actual GPU chip, with this deal they receive a certain amount of chips in certain timeframe including the reference design (on paper blueprints mostly) that AMD has built for this chip.
The reference design look like this for example :
http://wccftech.com/wp-content/uploads/2013/09/AMD-Radeon-R9-290X-Hawaii-GPU.jpg
This reference design is then effectively studied and reverse engineered by the board partners.
They then use their own designed or purchased components like PCB(green board part), VRMs (voltage regulators), coolers and other circuits to complete a design of the card.
The board is then built and the chip from AMD is added to the finished card.
Board partners even modify the "software" or firmware of the cards from AMD initial design to get different clock speeds.
Non-reference example :
http://www.techpowerup.com/img/12-03-15/167a.jpg
So now since you understand that, to get the supply increased that means that the manufacturers need to change a longstanding contract with AMD, then AMD has to go and suddenly increase the amount of chips made by Globalfoundries makes for them, which is another longstanding and a lot more volatile and BILLIONS of dollars contract.
So that is 2 major groups that need to suddenly increase production.
Then even if all of this is done, a chip takes a month to make.
Makes sense?