The Court knew more about the Constitution in 1973 also when the Court ruled by a 7-2 majority that abortion is constitionally protected right. A consevative justice appointed by Richard Nixon wrote the majority opinion.
Of the justices that decided Roe, 6 were appointed by Republican presidents - exactly the same conservative majority as this Dobbs Court.
A majority of the conservatives on the Roe court did not consider abortion a states right issue.
So what has changed since 1973 when a conservatice dominated US Supreme Court ruled that states cannot ban abortion procedures?
Republicans have changed. Conservatism has veered sharply right. Republicans have nominated and faught hard to confirm extremist Judges.