I actually wonder if they are really that antiquated, but rather that these schemes to bypass labor laws used to be called out and stopped, either by the unions in the 1890s or 1920s, or by the government in the 1950s.

That is, I wonder if the the deregulation era of the 1980s also deregulated labor practices to the extent that companies can now jump through these hoops in order to avoid labor laws.