I think that the topic is a bit misleading, as a DSG is technically a manual gearbox, simply with automated clutches. So whilst there may not be manual clutch changing, is it really the death of a gearbox that is connected to the engine via a friction clutch, no.
Due to Government intervention and things like CAFE, manufacturers have no choice but to go down this road. Same issue that is driving manufacturers to develop 10 speed gearboxes. Why, when you are tootling along in Eco mode, rather than Road Runner mode, it can disconnect the clutch and free wheel, turn the engine off, deactivate cylinders, etc. it is all to save a decimal point in terms of fuel economy. Plus, most people buy automatics (or DSG's).
You may be able to retrofit a manual, but given most of our driving is in the city and our roads are choked to the point of gridlock, where can you really exploit a manual, and even then, over here if you go a minute amount over the speed limit the Tax Office (sorry, the Police) will fine you (and out speed limits are 60mph).
I love manual cars, and manual motorbikes, but you can even now get auto motorbikes. But the only manual car we have is the 968. The others are an auto and a DSG (excluding the two motorbikes).
For cars like the GT3, I think it is a pity.
Even large trucks now can get automatic clutch manuals - where will it end?
Perhaps, there will be a very small manual option. To me, it is like one of the conversations about the 911 when Porsche was trying to kill it off. It was a difficult car to drive well, but if it was, it was very rewarding. Perhaps in the future, there will be something avant guard and defining about being able to pull up in a manual car, it may make more of a statement about the driver, than the car itself. Perhaps, because it will be unusual, it will be cool.
We can only hope.
Of more concern is the push for autonomous cars, where the driver no longer exists.