This vote seems to imply using a light crew is not capable of Olympic caliber sailing?

When I was on the sailing regularly, I used to have two crews, and would choose according to an upcomming regatta's wind conditions.

I guess, now, it is impractical for the skippers to have a light air crew?
Because if the wind picks up it is unsafe, uncompetitive, another mouth to feed/train?

It would be unfair (to crew) to qualify for the Olympics wtih one crew, and use another for the grand event.
(class rules say must use same crew you qualified with)

I thought the skipper's crew choice was part of the game?