Most of the thread is telling you the same thing: links stopped moving it, so go fix content. Sometimes that's right. But I'd check one thing before you accept it.
Same page, different class of link. I had a Canadian plumbing client parked outside the top 10 for months and the content was genuinely fine. Intent matched, internal linking was sane. What actually shifted it was cutting volume and going after relevance instead, and the page itself never changed a word. It sits around 1,818 organic visits a month now off a low-40s DR. So when 20 more of the same link does nothing, my read is that it's telling you something about the link type, not about links.
The other bit nobody mentions is decay. Placements get pulled, sites go dark, some editor rewrites the post and your link quietly vanishes. If you stop dead your profile is smaller a year from now even if none of your competitors do a thing.
So I never really stop, I just drop to whatever pace covers the attrition and put the rest of the budget elsewhere. And if you want to know which problem you've actually got, take one stuck page, send a genuinely different source class at it for six weeks and leave the rest of the site alone. You'll know.