So of course there are still critical sections--a critical section is a set of operations that must have uninterrupted access to a resource in order to maintain a desired level of consistency. If you have to yield (that is, `await` on a Promise or wait for the invocation of a callback), which sometimes you do have to do (i.e., you have to do IO, you've got a crunchy computation running in C++ outside of the JS loop, whatever), then you need to prevent access to that resource from whatever is being picked up next by the JS runtime while the first user is waiting for that IO to finish or that computation to come back.

To that end, locks are that "good state management" to which you refer. Most of the time one can use a mutex--the `async-lock` library is common--but I've even encountered cases where resource management must occur in structured forms and it was necessary to implement a read-write lock, where multiple readers can operate in tandem but all readers must close out before a writer can take control.

The basics don't change when your multitasking is cooperative rather than preemptive--all the same stuff still applies. This is not a controversial set of assertions. I don't understand at all where you're coming from.