Usually it's one or two people using their spare time to eventually get something good enough to work on work time occasionally unless it's 100% aligned with the company goals (e.g. a company like zeit or gatsby)

Parcel is good (and I use it), but it's likely if someone had pitched it internally I'd bet someone would have said "Webpack is good enough for us". At least that's how it would have gone at the places I've worked at.