I do think the whole concept behind Gulp, of creating processing streams through which files are fed to transform them, before writing to disk, is less useful than it used to be. This is because a lot of that functionality can now be handled by bundlers which understand the inter-dependencies between modules rather than just taking the input as a set of files. Also Node/JS's own async functionality is much more ergonomic to use than it needs to be, so additional async abstractions on top are less useful than they were.
[1] I'm aware of some issues related to file watching. See https://github.com/gulpjs/gulp/issues/2654