>there's no reasonable process to update the constitution.

Au contraire, a Constitutional Convention of the states to define the way they can all agree to be united.

Just like the first time.

There weren't that many states back then anyway.

You talking theoretically or in practice. Theoretically we could have Constitutional Convention of the states to define the way they can "all" agree to be united (just like the first time). In practice there is a higher chance of me marrying Beyonce