Yeah as far as product (people that do/make the thing being sold) is concerned, marketing/sales is a cost center and they should be making most of the money, since they're providing the actual value. As far as marketing/sales is concerned, the product is fungible and is a cost center, and they should be making most of the money since they're the only thing differentiating their org from competitors and making actual money come in. As far as accounting is concerned, the company doesn't make any money until they actually invoice and chase down and collect invoices, and if they don't
pay invoices neither marketing nor product will have the infrastructure they need to do their job.
Without HR/hiring, the other departments don't exist since they all need to be staffed. Without management, nobody knows what to do. Without facilities/IT/building manager, nobody has internet or water or desks or chairs.
And so on and so forth. Everyone is essential, and everyone also has an overinflated idea of their own importance and an underinflated idea of the importance of others.