The comment I was responding to at the root of this said:
It would take a constitutional convention to change
And my response was to point out that no, it wouldn't. It doesn't. It's still difficult, sure, but it doesn't require a constitutional convention to change.
Also, if you actually look it up, there are enough states that have already enacted the compact or are "pending" to get it done. So it's closer to being done than you are implying.