I agree with what you’re saying, but I also think the 10th amendment just hasn’t been enforced or challenged directly yet. We have always complained, but inevitably we just bent over and took it. The encroachment on our healthcare (or gun rights) could be the turning point though (I hope).
Even if SCOTUS rules in favor of the fed, but the States refuse to bend and the States even threaten to withhold fed taxes by its residents and threaten to arrest any federal agents attempting to enforce the disputed fed law, then what can the feds actually do?
The federal government doesn’t have enough law enforcement to enforce these federal laws, if directly opposed by the residents, law enforcment, & guard units of these conservative states and it is illegal to use the military to enforce domestic laws. If the military were used, I think much of the military would refuse and it could lead to open rebellion by the states. Of course this would be a fantasy because I don’t think any of our politicians have the balls to instigate this type of states’ rights showdown anyways.
What you are saying is that it basically comes down to politics. I agree. The 10th amendment begs the question, because it says the powers not delegated to the United States are reserved, but retains for itself the power to decide what those powers not delegated are. That is why the 10th amendment has no force behind it whatsoever. It basically says that whatever powers the national government doesn't claim for itself, you can have.
So it comes down to politics. The accrual of national power occurs gradually, and in such ways that the people at large do not understand or care. If the people oppose a law, there is a better chance it won't pass, because the jobholders like their jobs. And the people can vote in new people who will overturn such a law if it passes. But we have seen the power of incumbency, the complacency and outright ignorance of the people.
I actually don't believe nullification is proper. I view it as a sort of line-item rebellion. The proper thing would be to get a majority of states to agree. And then to hold a convention. But the politics of the people being the way they are, most people on our side believe that that cure would be worse than the disease, and they may be right.