What does Justice Kennedy's retirement actually mean for Roe v. Wade?

Whoever thought we'd still be talking about threats to women's rights to an abortion in this day and age. Isn't it all debated, settled and enshrined in law anyway?
Where abortion is concerned, nothing is ever settled, and, with the ill-timed retirement of Justice Anthony Kennedy from the US Supreme court, and the prospect of a second Donald Trump nomination, the perennial issue has raised its hoary head once again in the Land of the Free.
Not that it ever really went away. The landmark Roe v. Wade case, that gave women the constitutional right to a choice on abortion, happened way back in 1973. But the substantial percentage of Americans who still maintain that the rights of the unborn trump the rights of the already living have been chipping away at it ever since, with a surprising amount of success.
There was a flurry of media attention about a year and a half ago, after the death of Norma McCorvey (the "Roe" in Roe v. Wade, who championed abortion rights for many years, but who then "got religion" and started to oppose abortion), and President Trump's controversial nomination of anti-abortion candidate Neil Gorsuch to the Supreme Court. Much of the reporting then was along the lines of, "ooh, this is not good, but the make-up of the court is still such that a challenge to Roe v. Wade is not possible".
With Justice Kennedy's retirement, things could be about to change (the guy is 81, I get it, but could he really not hang on for a couple more years?). Kennedy is not exactly a Democrat, but he is considered to be a "swing vote", a reasonable man who votes with his conscience. In practice, this has meant that, over the last 30 years or so, he has voted to protect Roe v. Wade, as well as to champion progressive issues like gay rights. During his election, Trump campaigned quite openly on a platform that included a promise to select Supreme Court nominees who would "automatically" vote to repeal Roe v. Wade. Almost no-one expected him to get TWO such opportunities.
With an anti-abortion majority on the Supreme Court, what will probably happen is that various right-leaning States will enact abortion laws that challenge the constitutionality of Roe v. Wade, requiring a final decision from the Supreme Court. This could well result in an overturning of the law, or at least a significant erosion of its scope and effectiveness.
Perhaps the only thing standing in the way of this trajectory is the fact that Justice John Roberts is still Chief Justice of the Court. Roberts is a man of deep integrity, and a big believer in the idea that the court's decisions should be consistent with case precedent. Interesting times, as they say.