Continuing the above format, my own formula:
auto<paddle shift auto<DCT/DSG/SMT<manual
It's a close race between DCT/DSG/SMT and manual, though. The manual is cheaper and more fun, while the DCT/DSG/SMT generally produces better results.
Anyway, manuals won't disappear, and they're probably already as rare as they'll be as long as we have reciprocating piston internal combustion engines. They're just too fun. They'll completely disappear when we don't need to shift gears anymore due to a major change in basic engine design.