Clever accounting, one entity invoices the other and whatnot. One entity could be the reseller for the goods the other one is producing for example. Similar arrangements (no need for a foundation, just invoicing between your own entities) like that are often done e.g to pay your taxes in a lower rate jurisdiction than where you earn your money. You could set up a company that sells stuff and another company to hold the IP and then pay royalties. Etc.

ClosedAI is looking to do something similar, go from non-profit to for-profit. Personally I'm of the opinion that such a thing should warrant investigations and possibly indictments for fraud. Because it IS fraud, or at least false advertising. If I buy a Raspberry Pi, knowing that it's a foundation with a good cause, and the next day they announce they're starting a for-profit company to handle everything, that's very much false advertising, as the foundation model was be one of the factors in choosing which product to buy. If that makes sense.