There is no legal mechanism left that could correct course at this point. You would need to have a constitutional amendment to drastically reshape government and that's DOA. All that's left is snow decline and eventual dissolution
The absence of a legal mechanism does not imply the absence of a mechanism (or even the absence of a peaceful mechanism.)
While there is a legal process for amending the Constitution which, as you note, is likely intractable in the status quo conditions, Constitutional change—whether peaceful (even if there is the implicit consequence of force if compromise is not reached) or not—historically and globally is often an extralegal process that is retrospectively legalized, rather than a legal process under pre-existing rules.
The absence of a legal mechanism does not imply the absence of a mechanism (or even the absence of a peaceful mechanism.)
While there is a legal process for amending the Constitution which, as you note, is likely intractable in the status quo conditions, Constitutional change—whether peaceful (even if there is the implicit consequence of force if compromise is not reached) or not—historically and globally is often an extralegal process that is retrospectively legalized, rather than a legal process under pre-existing rules.