Another key difference over the last 15 years has been the introduction of awards and grants, which didn't exist then but now comprise $26.8M (15%) of their expenditures. This is where most of the ideological/controversial spending actually goes, rather than the salaries per se, but even more to the point, this one line item is more than 3 times their entire inflation-adjusted budget from 15 years ago ($5.6M times 150% CPI = $8.4M) and is still more than if we adjusted their entire budget using the hosting cost as an index ($5.6M times 3.75 = $21M).
[1]: https://upload.wikimedia.org/wikipedia/commons/a/a4/WMF_Annu...
Using hosting costs as an index is nonsensical. I wasn't able to find numbers for 2009, but since 2015 the monthly page views have remained almost exactly constant. So you might as well claim that they're vastly overpaying for hosting since inflation from 2008 is way less than 3.75x.
Ultimately every person has to decide for themselves whether they think WMF is a worthy recipient for their donations, but it is in no way operating on a shoestring budget nor staffed by volunteers anymore.