Not true. Congress can enact legislation correcting the situation.
In the time between now and them we can have some fun and make a point of beating these people over the heads with their own club.
And that's how we get Congress to act. The court will not change its mind.
You're right that IS how we get Congress to act, by creating such chaotic hell with the ruling that they must pass a referendum of sorts to rein in the SCOTUS.
But then that calls into question the long-standing debate over Madison vs. Marsbury.
Revisiting the latter should be a major campaign issue!