So I'm not sure why it seems to me like nobody is using it. I've been using it for years now it works just as good as back then.
So for example take js files
.pipe(transpile).pipe(bundle_split).pipe(sourcemaps).pipe(minify).pipe(hmr).pipe(versioning)...... etc
for css
.pipe(scss_converter).pipe(sourcemaps).pipe(minifier).pipe(hmr).pipe(version)... etc
i've been able to switch different stuff in and out thanks to community always wrapping newer tools as plugin.
like webpack as bundler, typescript/babel transpilers, auto prefixers, etc.
to me this step by step clear build pipeline makes more sense then hardcoded configs.
but gulp seems to be disappearing??
Not promoting this, but its a good Starter kit for lightweight sites which actually works and it's legit.
What i feel, solving a problem is much bigger part of a system then using gulp or webpack or likes.
Webpack has filled the gap, with it's unified plugin interface and is arguably much simpler and constrained than gulp. Cross-platform is also becoming less important as all popular OS's have implemented native unix shells.
Also, one of the main benefit's of gulp is running different build commands, which is only appropriate for a small portion of projects anyway...
The reason why gulp is dissapering is because newwer js frameworks like react and vue need webpack to be effective.
The reality is that nextjs and create-react-app are way superior, have TypeScript and Webpack configurations out of the box, and they have their own build process. No reason to use Gulp anymore.