Isn't that kind of problematic too though? The idea that donations may only go to organizations that would struggle otherwise? (I know I'm inferring something you didn't explicitly say, but I do think that is a fairly common sentiment as well)
I'm ok with donations to a specific mission or a group with a very clear this-is-what-we-need-to-fund style goal and budget, and obviously if they are achieving their mission then they don't need more donations.
I'm not normally comfortable with the broad-mission style organisations. A large pool of money to be spent on an amorphous goal, by a group of essentially unknown people of unknown ability and beliefs? That is a scandal waiting to happen, and probably going to be mired in admin fees and corruption over the medium-long term if it isn't already.
Any charity that isn't struggling to keep the lights on is fundamentally suspect.
A big difference that you might be looking for is that nobody is keen to give money to a company. People have (surprisingly effective) methods to find the cheapest producer. If the government is behaving appropriately this effect generally squeezes profit margins until they are uniform and thin. In theory. Practice is often close enough to theory to keep the system humming along.
By having a high expense situation and constantly begging for donations, it puts wikipedia, the main venture, at risk if other wikimedia ventures don't pan out.
If it was a struggle to keep wikipedia's lights on, I'd consider donating myself, but if it's for wikimedia to expand other projects with questionable benefits, I'm not inclined, and portraying the latter as the former rubs people seriously the wrong way.