I bought a USB to serial converter device delivered to my door from China for half the price of the FTDI FT232R chip alone in 10K volumes. The device has other semiconductors, headers, USB connectors; is well laid out on the PCB. It works on 5V, 3.3V and 1.8V logic and works a treat.
It is possible employees steal chips in China, the chips are fake, the chips are reused, or maybe FTDI provides special prices to the Chinese. My guess is some back alley operator reclaimed the FTDI chips off old boards.