If you look at these two links, Roe V. Wade was decided January 22, 1973, since that time there have been two congresses where a super-majority with a filibuster proof 60+ votes in the senate and the house in 75 and 77. A Republican (Ford) was in the president’s office for one of those leaving a single time with Carter in 1977 when it would have been possible without altering the senate rules to codify the decision, assuming that the R’s would have objected as they have from the beginning. I guess you can take it up with Jimmy that it wasn’t pushed into law back when the SC had just made their stance clear a couple years prior.
The next most viable times would have been in 1993 with Clinton and and 2009 with Obama, and both of those would have needed to either amend the rules or convince some R’s to go for it. It seems you’re overestimating the power they’ve had since the matter was before the SC the first time, particularly when it had been seen as a settled matter for more than 2 decades before the earlier of those.