Earlier quoted context omitted.
That’s why the display guidelines stipulate that DOIs are always expressed as URLs.
Sure, but 10.1083 is still a shitty link compared to nature.com, independent of which url prefix is used.
The resolvability of a DOI is obviously important, and you have found a few examples where the steward of the content (ie publisher) hasn’t updated the links. But in that case DOIs can in theory be redirected to archived versions. That's the price you pay for a large, diverse community of publishers. Don't imagine that publishers would magically be any better at fixing their own websites.
But more broadly, as identifiers, having an agreed scheme helps link publications, datasets, other entities such as funders and institutions. It allows discovery of metadata in a way that’s discoverable by all.
Someone will want to follow those links in 100 years and whatever state DNS or WWW is in, the metadata will be in an open archive somewhere.
(I'm at Crossref, AMA)