The value of attending Harvard comes not from the education itself, but the signalling which indicates that you had the abilities or achievements to get accepte

The value of attending Harvard comes not from the education itself, but the signalling which indicates that you had the abilities or achievements to get accepted in the first place. If Harvard or Yale start publicly accepting that a proportion of their students simply paid their way in, then this knowledge shifts from being an implicit understanding/public secret to one that is publicly acknowledged and widely publicized. If the names of those who bought places are publicly announced, then this dries up the pool of future 'donors' because the signalling effect disappears when everyone knows how you got in. Conversely, if they keep the names anonymous, this demeans the value of the degree for everyone, because people will then cast their aspersions on all future ivy league grads.