In a nutshell, what it took is not simply "Republican" judges, but
installing conservative justices prepared to reject the precedent [...]
Justice Alito’s majority opinion [endorsed by 4 other justices: Thomas, Gorsuch, Kavanaugh, and Barrett] not only sustained the Mississippi law but also said that Roe and Planned Parenthood v. Casey, the 1992 decision that affirmed Roe’s core holding, should be overruled.
Chief Justice Roberts had a somewhat more nuanced position wanting to only greenlight the law at stake (Mississippi wanted a 15-week deadline), but the other conservative justices said that given the spate of other state laws likely to reach the court subsequently, making this bold reversal was the best course. From the opposing side it simply looked like
“A new and bare majority of this court — acting at practically the first moment possible — overrules Roe and Casey,” they wrote, adding that the majority had issued “a decision greenlighting even total abortion bans.”
And if I'm to try to explain a bit how this came to be, three main elements are probably at play:
- Better vetting of nominees inside the Conservative camp;
All five justices in the Casey majority were Republican appointees, a measure of how the world has changed since then.
the justices who voted to overturn the right to abortion reflected something more particular: They were chosen for that specific task. Reagan ran in 1980 on a Republican Party platform that pledged to “work for the appointment of judges at all levels of the judiciary who respect traditional family values and the sanctity of innocent human life,” and every Republican presidential candidate since then has run on a similarly worded platform. (The only exception was Donald Trump’s reelection campaign in 2020, when the Republican National Convention adopted no platform, the party’s only platform being Trump himself. During the 2016 campaign, Trump said that if he got the chance to make Supreme Court appointments, Roe would be overturned “automatically.”) Of the seven justices appointed by Republican presidents since Reagan, only David Souter, named by President George H. W. Bush, failed to deliver; Souter, who retired in 2009, was part of the five-justice Casey majority. By contrast, Bush’s other nominee, Clarence Thomas, now the Court’s longest-serving member, has proved a banner-waving success. Not only has he spent his three decades on the Court in pursuit of Roe’s overruling, but his concurring opinion in Dobbs added revisiting the Court’s precedents on same-sex marriage and even on birth control to the Court’s to-do list.
Better poker-face in Senate hearings from the nominees themselves, avoiding their nomination ... being Bork-ed there by revealing their stance on Roe specifically. (As mentioned in the other piece, only Alito had taken an open stance on overturning Roe, but his  statement was pre-Bork , and in the context of applying for another job.)
Thirdly, the Senate became more partisan, passing nominations on a narrower majority (from the first source):
A political scientist would have been farsighted indeed to anticipate what happened to the Court from 2017 to 2020: that a president who lost the popular vote would manage to lock in a conservative supermajority with three appointments, all of them confirmed by the narrowest of margins—following the Republicans’ abolition of the filibuster for Supreme Court confirmations—by senators from states that collectively contain less than half the country’s population.