I think io_uring more or less works as advertised now for the key thing it set out to do, but it removes one bottleneck in a larger system of network processing

I think io_uring more or less works as advertised now for the key thing it set out to do, but it removes one bottleneck in a larger system of network processing, so you can switch to io_uring, yet potentially without any other changes, a real world application can hit the next bottleneck due some adjacent architectural decision (or performance regressions as implementations are changed to accommodate an expanding envelope of uses).