A foundation with 20M$ and these ambitious goals is a gift for the society. However, it is also the typical American way of company-society interaction. The actually intended way is called "paxing taxes". Dropbox, like a good part of the US tech companies, has it's European site in Ireland, a country known for its low tax rates [1].
[1] https://www.theaustralian.com.au/business/business-spectator...