Justices are voted in by Senators. The Senate is weighted much more heavily to less-populated (conservative) states than even the Electoral College.
If you can't put it together how conservatives have retained power by making their own votes heavier, and that their fight is against representative democracy, I'm not sure I can help you.
Yes, the math works. SCOTUS is heavily conservative.
If Dems & Leftists want the wins, the numbers on the ground need to be overwhelming.... consistently.