I am sorry but law is for every citizen who has to obey it, so it is for everyone and everyone have to understand not only lawyers, are you sure you know what you are saying?
There can be no lawyer at every time you do almost anything in life, be in traffic, raise children, participate in education, purchase something, travel, anything! Do you need an engineer sitting right next to you when you turn on the light or operate a vechicle? No! You need them for advanced things.
If you argue that ALL law have to be understood only by lawyers then you are very very lost! What you have to obey, you have to understand! At least the relevant part (nuclear waste storage is perhaps not for you, I am just guessing), but even knowing which part is relevant you need to understand! Not enough lawyers to sit next to everyone guiding through everyday life that is regulated by law!
It is difficult to understand because it made to sound ominous (fucked up for everyone), that's it, see the article. Form over essence. Also evolving without effort for restructuring so it becomes overcomplicated (see article). All formality over practicality and common sense, that's why it is so convoluted, or "it’s an accidental property", mimicing for centuries.
Also don't mix up everyday language here used with friends over a beer that could be vague for outsiders - or themselves - but there ARE ways to be specific and understood with ordinary people too using the generic communication method law uses too: language. That could been used, that is being used in other areas in communicating towards layman (like doctors, I mean the smart ones, not engulfing you with latin explaining your condition and prognosis, right? Also instruction manuals for complex gadgets are not in ancient greek just for the sake of it, right, but ordinary and specific or even formal language that are still being understood by the ordinary consumer, as that is important.)
Additionally: "Lawyers tended to prefer plain English versions of documents, and they rated those versions to be just as enforceable as traditional legal documents.". I rest my case.