these gifts have been known about for a long time
No they haven't. That's why it's breaking news when they get discovered.
In my entire life I have never seen any evidence that for supreme Court justices things influenced their ruling.
How would you possibly know what this looks like when, as you concede, there never have been meaningful investigations into the justices?
The history of the justices predicts their current rulings and does it amazingly well.
No better than the history of their acceptance of lavish gifts from ideologically motivated rich people.