I vaguely recall that there are classic levels in Jewish philosophy regarding philanthropy, and among the highest is to give with no expectation of any return whatsoever: that means not only giving where it matters, but to do so anonymously, to organizations that don't benefit you (no opera companies), and to people with no ties to you. In this respect Chuck Feeney has been incredible. This is not to dismiss the like…
I'm not trying to downplay him in anyway. I'm just saying that $2M in the bank is still an extremely comfortable life so there is not much hardship to be had in giving up everything over that.
Also, as for donating anonymously vs non-anonymously I do it non-anonymously as trying to add social proof that you should donate. The more it appears normal to donate the more people will donate, or so I believe. If I could do that anonymously I would but people read me (my blog or other things), they don't read anon's blog/tweets, whatever.