@A-Team First I need to compliment you for opening this thread. One look at the map and it is very obvious that Afghanistan is as tied into the fate of the CPEC as Pakistan for the simple fact (Indian's need to note this) that major portion of Afghan population live adjacent to Peshwar. In fact Kunduz - Kabul - Peshawar - Islamabad - Lahore lie on the same transport axis. Indeed Kabul and the region around it with very high population falls within the Indus Basin catchment area via the Kabul River. Below. Population density map.
The above map shows the transport corridor that connects the high density areas of Afghanistan (including Kabul) to high density areas of Pakistan (including Islamabad). Of course the eastern point on this terminus is Lahore which is adjacent to Amritsar in Indian Punjab and I don't think that border is going to open anytime soon.
The Af-Pak corridor is marked red. However what is interesting is that one of the alignments of the CPEC (marked green) running from China to Islamabad (where it meets the Af-Pak corridor) on south to Gwadar and Karachi. This means that potentially CPEC could impact Afghanistan as much as Pakistan. This is plainly obvious by looking at the maps. That this potential will actualized very much depends on regional politics which is something that hot heads on both sides need to bear in mind. Over the long term those Afghan refugees everybody complains so much about might turn out to be asset for Pakistan as their presence will reinforce the Af-Pak corridor which links into the CPEC near Islamabad/Taxila.
The real question that needs answering and OP brought that up was "what is CPEC all about". I can't believe that after so much song and dance about this CPEC the real question as to what it is all about has not been resolved. So here is my take on it. Imagine this desert below.
There is almost no economic activity. It is almost disconnected from the vibrant pulsating centres of world economic powerhouses. Now imagine your going to build a canal through it. What would you look forward to? Charging
transit fee for the water
discharge along the canal? Or
emergency supply of drinking water to some town downstream?
Well you could just dream of those two benefits that the canal would bless the desert inhabitants. Or you could think
big. You could think of the canal as offering huge potential to bring about revolution to the backward desert.
(i) The desert could be irrigated to become huge farming country.
(ii) massive agriculture exports
(iii) towns develop to service the farms
(iv) industries develop to service agriculture
(v) exports connect you to markets far way. Imports come from far away.
(vi) You are now connected to the world which brings new ideas and ways of doing things.
In the same way do not regard the CPEC as strip of tarmac. Regard it as corridor to China which is pulsating economic powerhouse. Down that corridor will come cascading Chinese goods, ideas, industrial investment. Yes of course the Chinese economic wind will kill many industries in Pakistan. But why should anybody care? Do you guy's want rackets run by corrupt rentier class to continue milching the Pakistani customer?
As much as Chinese influence will kill many decrepit industries inside Pakistan it will also hasten new investment by Chinese companies which will bring their way of doing business to Pakistan. This is comparable (to a degree) how new entrants to European Union go through after joining. As they join the old inefficient industries are wiped out as western products flood the market. However soon enough those western companies start moving some of thier operation over to those countries because of cheap labour.
So it all depends on Pakistan. If it does this properly Pakistan will get flooded by Chinese products followed by Chinese companies moving in. A common market could come about out of CPEC. Will CPEC potential be exploited by Pakistan. My concern is that Pakistan's fascination with run awy religion might trip CPEC. If Pak can muzzle the mullahs and instead create pragmatic business climate than this could be game changer and Afghanistan being next door could also be sucked into this.
@nang2 Excellant points you make. If Pakistan can follow China in letter and spirit then CPEC would turn into 21st century success story. In thirty years time if Islamabad Airport is recieving 10 million visitors from China and the airport is linked daily to every major Chinese city than CPEC will have been a "game changer".