Gulp has/had the right approach. There's only so much flexibility and complexity configuration format can support without becoming strange copy-pasted incantations that can only be reasonably expressed and clearly visualized through code. And they've proven that, eating Grunt's lunch, but then they blew it with never-ending alpha and general stewardship fail.

And with regards to Parcel vs Webpack, it's not (at least not yet) even a competition since webpack 4 is basically zero-configuration and is so much more advanced tool at all levels.