Orphan pages rank and well-linked pages stall because internal links are one ranking input among several, not the verdict. A link count tells you how connected a page is inside your site; it does not tell you whether the page is relevant, complete, or trusted enough to win its query. Once you stop treating internal links as the full story, the paradox dissolves.
An orphan page can rank when something else carries it. If the page has earned external links from other sites, those references supply authority that internal links never had to provide. If it is discoverable through a sitemap, Google can still crawl and index it despite the missing internal links. And if the content is genuinely the best match for the query, strong intent fit and depth can outweigh a weak internal position. Internal links would help that page, but they are not the only road to the signals that rank it. A single in-depth guide that a few other sites have linked to can outrank a thin page that every page on its own site points to.
The well-linked page stalls for the mirror reason: the links were never what was missing. You can aim a dozen internal links at a page and it will still lose if it answers a different intent than searchers want, if it covers the topic more thinly than the pages beating it, or if the domain simply lacks the standing the query demands. The links did their job, discoverability and passing along whatever authority the site already holds. They cannot conjure relevance or trust the page has not built, so a page rich in internal links and poor in everything else sits exactly where its weakest signal leaves it.
The practical correction is to stop reading a link count as a ranking prediction. When an orphan ranks, look for the external authority or content quality doing the work. When a well-linked page stalls, check intent fit, coverage, and trust before adding more links. Links are one lever among several, and the page moves on whichever signal it is shortest on.