To add to my own comment, this [1] was the submission that I originally had in mind. It was in the 2007-2008 operating year that Wikipedia's expenses crossed the $3 million threshold. In 2015-2016 the expenses were >$65 million. In 2019, they were $91 million. Remember that the content creators work for free.
The reports are available here [2]. Looking at the most recent report here for FY18-19, the amount spent on hosting is $2.3 million. That's less than half of the "donation processing expenses"!
[0] https://news.ycombinator.com/item?id=3112115