Of course, standards vary significantly institution to institution and even person to person, and highly technical, skilled people are not indicative of full capability of reading, let alone reviewing the topic, doubly so when it is original research.
It has the odd effect of making this stuff comprehensible only to those that essentially already know what it is, and possibly a few people academically adjacent to those people.
Other people can decipher it, after long and arduous labor, but it essentially requires rediscovering the path that brought it about, knowing what the outcome will be. In that sense these papers are less useful than they seem.
Academia is a little like religion: to outsiders the language and rituals make little sense, only those indoctrinated in its tenets can achieve enlightenment.
That said, conveying an idea in an easily understandable way is hard and some authors will do better or worse than others. Also papers will usually not purely present the new idea but provide some context so that the reader only needs to be familiar with the topic up to the context but the amount of context given will vary a lot between papers.