That's nominal profit margins. It doesn't take into account the way that different parts of these conglomerates take money from one pocket and put it in the other (e.g. insurance and Healthcare providers), which means it doesn't show up in the profits for your first pocket. This is why the fact that Healthcare platforms are vertical monopolies (not just horizontal monopies) is important to this conversation.

(separately, profit capping rules means that once a monopoly is cemented, once a company has moved as much as it can from one pocket to the other, there's an internal incentive to spend money on bureaucracy).