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.
Even if you study textbooks, which themselves suffer the same fate, requiring other textbooks or knowledge of terms and notation as prerequisites, and have knowledge in the field it doesn't mean you can understand most papers. Fields and subfields have their own (obscure) terminology and notation, often individual practitioners do. Even if they don't terminology and notation isn't used consistently, which becomes critical when you're trying to learn and understand.
I'm just lamenting how inscrutable this knowledge is and how sad and frustrating that is. Most of this stuff is not that complicated once you know what they're actually talking about. Instead you end up banging your head against the wall for hours trying to divine the intent of the author or go on endless yak shaving expeditions trying to nail down terms and concepts.