I would say that engineer/product/analytics salaries are part of the cost of running and updating a webpage. Then you have HR which is needed to support those employees and Legal which is especially needed given the high risk nature of Wikipedia.
Good luck keeping Wikipedia up in a useful manner without those people.
edit: Then you need Finance to help handle the costs responsibly. Then you need Fundraising to help raise the money needed to pay for all that. Then you generally want some Marketing/Branding/Communications to help with the whole talking to external humans part.