But I don't think it's valued much on the open market.
As in, it's hard to be recognised for that kind of skill. Established, larger companies tend to have a structure in place and, at least on the open market, try to fit people into narrower roles. Even if there's a laundry list "tech stack", it's usually a narrow role.
As ritchiea said, it can seem as if the only place where the range is a good fit is at early-stage startups, with plenty to do and good judgement needed, but limited earnings on offer.
I think the OP has a fair point about one mode of development being substantially different than the other, but I don't think it's appropriate to partition them into separate roles. Part of engineering is knowing which path forward is most appropriate under uncertainty, given information about the team's skillset composition, available resources and time constraints.
A good software engineer is capable of holistically considering the options. If your third party library is considered like a paved road, this involves knowing when your vehicle can tolerate veering off the paved road, and knowing when you need to build a new road yourself.