It’s interesting and is actually an under discussed but important topic in EA community.
However, I think you could compare direct work vs donating to support AI safety research directly, not donating Givewell(which mainly focus on improving global health) Because for some people, donating to longtermism funds is much more effective than GiveWell.
Could this news really be the evidence of “It’s probably in the future the funding gap would decrease significantly”. Of course in the future 3 years there may be a lot of small donors coming from Anthropic, but what if Anthropic is surpassed by other AI frontier labs in the future?(like: Open AI, Google Deepmind) There may be way fewer donor in these companies. Therefore, the increase of funding may not continue long-term. (Though, I’m very uncertain, welcome to comment below to share your intuitions about this).