pipes, scalar objects and on?

Hi, I tried to read on why the pipe RFC failed but by and large I also failed. The discussion on https://github.com/php/php-src/pull/7214 is very short. https://externals.io/message/114770 is not so short but it seems not to cover the latest version which uses first class functions? Could someone please give me a summary why it failed? I really would like to see it succeed :) I am writing code if not daily but certainly weekly that certainly looks like a pipeline. Of course, if the preference is to bring nikic/scalar_objects into PHP core, that'd be even better :) but I am aware of https://github.com/nikic/scalar_objects/issues/20#issuecomment-569520181 so that's perhaps not going to happen any time soon. Thanks - ChX