In the same period, expenses have grown from 25k to 80M, a 3200x growth. [TFA]
[1] https://stats.wikimedia.org/v2/#/all-projects/contributing/e...
As it has attracted global attention and ever more significant influence on people worldwide, Wikipedia's threats are likely more varied and insidious than they were in 2004. The cost of offsetting these threats may not relate to the volume of edits.
I'm not, by the way, suggesting that a 3200x growth in expenses is inherently unjustifiable, just that it should in fact be justified.
https://meta.wikimedia.org/wiki/Wikimedia_Foundation_Annual_... Planned spending 2019 ~92mil
https://stats.wikimedia.org/v2/#/all-projects/contributing/e... - ~130% page edits growth 2012-2019 (~35mil expenses, a 260% increase)
https://stats.wikimedia.org/v2/#/all-projects/contributing/e... - ~80% page edits growth 2015-2019 (~65mil expenses, a 140% increase)
The rate of increased page edits is closer and closer to the rate of increased expenses. I personally don't think that's a convincing argument, because I haven't seen this massive improvement in tools to justify the extra costs(most of the extra expenditure doesn't seem to be on development, anyway), but I don't think the argument can be dismissed out of hand.