Supreme Court can still function to validate laws against founding constitutional rights.
But, I do agree, majority will have its way most of the time. If minority has a grievance, it has to address the same way people holding any other minority of opinion would deal with it... make majority see things your way.
Gay partners should be able to adopt. Make majority see it your way. We should have not criminalize marijuana use. Make majority see it your way.
In fact Civil rights have more advantages than people with majority race, ethnicity, religion but holding a minority opinion e.g. euthanasia. At least for Civil Rights there are courts to go to, majority has agreed to have that as a recourse just for Civil Rights opinions.
I honestly think minority Civil Rights are only possible when majority is doing good, economically and emotionally. Because, Civil Rights need to be enforced through education, and might of the state, which is the majority at the end of the day.
Sure, Gay rights and no slavery exists in USA, mostly because majority sees it that way. In Saudi Arabia or in ISIS territories those rights don't exist.
Civil Rights only exists where majority agrees that Civil Rights deserve to be honored. If they didn't, it wouldn't. We can feel as uncomfortable as we want about it, but that's just how the world operates. Unless there are technological advantages where one assumes god position enforcing Civil Rights of each individual without any external dependency, I don't see if that way of how the world operates could ever be changed.