Hate to be a party pooper but what kind of income do you beleive is sustaining for a national museum with extensive archives, repositories, conservation costs and ongoing collection needs, quite apart from simple building maintenance, outreach and staffing?
$2.6b generates at best of the order $200m in usable funds. I would be amazed if that is even remotely close to the operating costs of an institution like this.
Reading https://www.si.edu/sites/default/files/oa/smithsonian-2024-w..., they’re spending $1.7b a year.
Interesting financial report, by the way. Lots of info about what they do with photos, lists of who donated money, and then, the real financials start at page 79 of 87 and end on page 82.