And of course the clothes worn by the First Lady serve to promote the fashion industry. (In trying to find an answer to the OP, I found a fashion industry article criticizing her for wearing clothes for a particular event from a French designer.) As said upthread, designers loan gowns to her for much the same reason that they lend clothes to actresses to wear to award shows; it’s good for business.
At this point, it doesn’t look like we’re getting any closer to a factual answer to the question in the OP. Those who wish to discuss the First Lady’s fashion choices may open a new thread in IMHO.
If someone has some factual information to add regarding the OP, PM me and I will reopen this.
Colibri
General Questions Moderator