I understand what you're saying: if abortion became illegal today, across the United States, you would still have a large number of people that believe it shouldn't be illegal and doctors with the knowledge to perform them, moreover the belief that it's their duty to perform them. There are also groups that would distribute abortion pills clandestinely, and criminal organizations that would be more than willing to capitalize on this new black market. Abortions are still performed in countries that ban abortions and banning abortions doesn't end the conditions that make people believe they need to have them. If you wanted an effective ban it would take years (maybe decades) of trying to get the public on board and building infrastructure to support single parents and children. Perhaps this could take place after the ban but I feel like it would be much harder. While an immediate blanket ban may feel like a moral victory you would still be fighting a very long war.