Memory models don't usually explicitly guarantee that writes "eventually become visible". They're usually written as ordering guarantees for when a write becomes visible, such as happens-before relationships. Obviously, for multithreaded programs to be useful, the writes have to eventually become visible to other threads/groroutines just like you want all sorts of other operations to happen in finite time that are not explicitly guaranteed by standards (like whether a thread/goroutine eventually starts.)

Well said. But how much finite time are we talking about (for writes to become visible)? Does it differ between architectures? Can there be extreme edge cases?