The idea that the legislature would lower the retirement age to 53 in order to remove them all is just beyond wild.
Then they would install 7 new Justices who would have to commit in advance to reversing the prior Court’s decision — that tells you everything you would ever need to know about anyone who would pledge to do that.
Three Justices voted in the minority, but you can’t exempt them from the retirement because they might object to a corrupt process to remove their colleagues for no reason other than naked partisan politics.