Exactly.
First of all a distinction must be made between legacies and big donors. Legacies are often dismissed as getting in only because of their legacy status, but I'd wager that their grades, test scores and other accomplishments put them on the admissions bubble already. Dropping the SAT isn't going to help Harvard let more of them in because they're probably doing quite well to begin with.
Donors' children may have more wiggle room with their grades and scores, but they're a much smaller population than legacies and the idea that Harvard is going to drop standardized testing just to marginally increase the numbers of donors' children they can let in, like some nefarious plot to marginally increase donations, is laughable and culturally tone deaf.
Harvard administrators have no interest in drastically increasing the number of legacy or donor students. The admissions rates for those groups have likely been static for decades.
Harvard administrators do, however, have a huge interest in increasing black (and to a lesser extent Hispanic) admissions rates. This is made much more difficult by standardized testing scores.
In fact much of the stated justification by the schools and other intellectuals for dropping the tests is that it discriminates against the poor and minorities, which is ironic because it is one of the factors of admission least correlated with wealth and also because many minority groups do better on the test than the overall test taking population.