At the moment, they have €250M in assets, and a further €100M endowment. Their assets have increased by double-digit millions every year for a decade.
In my opinion, the yearly fundraising campaign is highly disingenuous. Basically, they are begging for money, claiming it is to "keep Wikipedia running". In reality, Wikipedia-the-website is an unlimited cash cow used to fund tangentially related pet projects at the Wikimedia Foundation. In 2008, the expenses were €5.6M. 2021 expenses are up to €112M - and I can guarantee page views did not increase 20-fold!
At the moment, hosting costs are about €3M / year. Let's round that up to €10M for sysadmin and development salaries, and they currently have enough money to keep Wikipedia running for 35 years.
I'd be more than happy to donate to keep Wikipedia itself alive, but at the moment donating money to them is basically the same as throwing money in a bottomless pit.