No. All the writing and most of the moderation is done by volunteers. The closest to that on the Foundation's payroll are the about three community managers. The Foundation does employ the engineers writing the software, the sysadmins keeping everything running, a UX team of 14 people, a lot of people related to fundraising, as well as outreach and public relations, some legal staff and various administrative staff. There's a full list of employees and contractors at https://wikimediafoundation.org/role/staff-contractors/

It's well-documented that active writers are paid shills for corporate clients. I've read interviews where the writer brags about his "ownership" of certain pages.