With io_uring, every line in an application that calls read/recv needs to be refactored, along with much of the surrounding context. io_uring doesn't replace poll/epoll, it effectively replaces typical event loop frameworks. You can integrate io_uring into pre-existing event loop frameworks, but the event loop framework will end up as a 99% superfluous wrapper, at least on Linux.

Note that many applications don't use event loop frameworks. For simple applications they can be overkill. Even for more complex applications, it may be cleaner to use restartable semantics (i.e. same semantics as read--just call me again), especially for libraries or components that want to be event loop agnostic.