On Friday, its leaders issued a news release excoriating Mr. Lew: “Women on 20s considers it deeply disturbing that Secretary Lew would renege on his public commitment to prominently feature a single woman on the next new bill.”

“With this decision, Secretary Lew is proving, once again, that in America it’s still a man’s world,” they added. “It was a chorus of mostly men who implored him to keep Hamilton on the $10, and he listened.”

Indeed, it was Mr. Lew’s listening — not just to Hamiltonians, but to the unanticipated millions of Americans who responded to his June invitation to recommend a woman for the currency — that accounted for his missing his self-imposed December deadline. He was hearing a cacophony of conflicting opinions, mainly pitting some women’s groups against Hamiltonians.

Now leading the Hamiltonians, in effect, was Lin-Manuel Miranda, the star and creator of “Hamilton,” who, in the words of the musical’s Hamilton, was not throwing away his shot. He pressed Mr. Lew to keep Hamilton on the $10 bill when the Treasury secretary and his wife saw the musical. Mr. Miranda recently said on Twitter that Mr. Lew indicated “Ham’s fans” would be happy with the ultimate decision.

Mr. Lew also listened to the outspoken leaders of Women on 20s, who were invited to his event last June. Yet it was perhaps never possible that he could satisfy them.

With online petitions and efforts on social media, the group’s leaders — the founder, Barbara Ortiz Howard, and the executive director, Susan Ades Stone — campaigned to put a woman not on the $10 bill but on the more numerous $20, the common currency of the ubiquitous automated teller machines. Their activism, combined with Hamilton’s newly untouchable status, eventually led Mr. Lew to consider a not-so-Solomonic decision to leave Hamilton on the face of the $10 and have a woman oust Jackson from the $20.

But Women on 20s would not consider that a victory, the group’s Friday statement made clear, since the new $20 would be years away. It wanted Mr. Lew to redesign the $20 ahead of the $10, or concurrent with it.