Not to mention all the groups that arose with questionable polls "proving" Americans had woken up on guns, and would vote against politicians who opposed gun control. The only people who vote on guns are pro-gun people. That has always been the case.
I doubt it would have worked, but Obama should have nixed Feinstein's automatic weapon bullshit. It wouldn't even be a concession - banning automatic weapons would not lower gun crime given the fact that the majority of gun crimes are committed with handguns. Focusing on background checks, shitcanned straw purchases, etc would have made far more sense and perhaps been less controversial. I still don't think it would have worked though.