Scalia’s point on 1A was that it was never intended to break new ground, it was crafted simply to declare that “the” freedom of the press - already existing freedom of the press - would be respected. But already existing freedom of the press was already limited by libel and pornography laws.Thus, 1A did not touch libel law. And that is why libel law survives at all. But Sullivan didn’t consider that there was such a thing as a journalism cartel which has to be blown up with antitrust law and, IMHO, libel law.
The closest that early Congresses ever came to violating the First Amendment was the Sedition Act, which is believed to have been aimed at the muck-raking Aurora newspaper. No case on the Sedition Act ever reached the Supreme Court, but in recent decades the Court has indicated in dicta in various opinions that the Sedition Act was unconstitutional.
So how does the First Amendment now apply to the states? Based on the Reconstruction era 14th and 15th Amendments, the Supreme Court adopted the doctrine of incorporation and has gradually applied most of the Bill of Rights to the states.
The problem with Scalia's reasoning about original intent is that it moves the gravamen of constitutional analysis from the text to the limited and obscure historical records of the early federal era. This criticism was sufficiently potent that Scalia himself took to referring to his judicial philosophy as textualism. Original intent still matters, but subordinate to the text of the Constitution.
On the whole, we are better off if constitutional analysis revolves around the words of the Constitution and good reason instead of conjecture about intent. And, as now applied, the First Amendment applies even to libel law. For that, we can thank Reconstruction era.