Wikipedia makes most of its money from donations, with some money coming from other sources like commercial API access. It consistently raises more money than it spends and has been building an endowment. However, that income mainly comes from the fundraising drives.

Wikipedia has an endowment, but it isn't enough to run the website for more than a few years.

In terms of expenses, the largest expense is in having staff to run the various websites and foundation. Charity auditors rank the foundation highly on expenses, so the foundation is likely not overpaying staff.

Wikipedia needs donations to survive, but it isn't struggling. If you feel like you have better things to donate to, it is probably ok for now.