Takes a long time for the court to overturn bad law and errors in opinions.
50 years.
It took nearly 100 years for the USSC to finally, in Brown vs. Board of Education, eliminate the horrible Dred Scott decision of 1857. This despite a couple of Constitutional Amendments in the intervening years that made it clear that segregation was atrocious.
I suggest we simply praise God that we saw this decision in our lifetimes.