To speed up assembly production, which is where any lag will be, The RPi should come default without the RCA, Audio and GPIO connectors. Perhaps even some others that are thru-hole. Just let the end user determine which connectors he/she wants and supply them in a bag. Will save alot of time in production not having manually soldered parts in the mix.
It seems everything else I buy, especially stuff from China, there is some assembly required anyways.
Deleting those items from the build will make very little difference to the assembly process - probably only a matter of seconds. Getting the cost down is the most likely reason for deleting components, and if, as it seems, they can be produced fully populated within the target price, then not only are they provided, but a de facto standard is established for peripheral attachment via these headers. It would seem sensible, on balance, to include them fully fitted.