Because in the UK you have a system for overriding such rulings by I believe simple majorities. In our nation the only way to legally override a supreme court decision is via constitutional amendment which requires supermajorities in both houses, plus a supermajority of all the states. (State=UK Province).
Ever hear of Court Packing? Congress & the president can add as many judges to the Court as they please. One could flood the court overnight with 10 extra judges.
It's Congress and the President, the whole ruling-class structure, not the Court, which holds up things.
Carrol