For a brief moment before epoll came along it looked like Linux would get /dev/poll.[1] In fact, IIRC, epoll started as a /dev/poll implementation. I don't think Sun's /dev/poll ever saw much uptake because, aside from the limitations mentioned the kqueue paper, the pace of software development was much more rapid and dynamic in the FOSS and web worlds, and the center of gravity had already shifted to BSD and Linux.
For better and worse, Linux developers seemed more inclined toward adopting extensions from SysV and SunOS/Solaris than from the contemporary BSDs.
And then Solaris added EventPorts in reaction to kqueue. Arguably they should have just adopted kqueue. Would be much better if both Solaris and Linux had just adopted kqueue. Having that unified accross the 3 major server OSs would have been helpful.
We even went through a phase of email on OpenBSD before being bought by a company that insisted on Exchange.
Linux didn’t seem to pull decisively ahead of the BSDs until multicore x86 became mainstream. Up until then it always seemed flaky.