Experience convinces me more and more that resorting to jargon in philosophy is typically (though not always) the result of lazy writing and bad writing.
I have touched on the subject before. Since then, I have had more opportunities to practice the avoidance of jargon and abstruse language. I find that persistence usually leads to discovering elegant solutions, even when tasked with complicated explanations or esoteric subjects that might seem to require laxity and compromise.
Expressing the same ideas in plain-language philosophy very often requires more work to achieve. For example, retasking recognizable words or phrases in order to describe unusual concepts can usually be done, but to do so economically presents a challenge. However, since much of the same work contributes to clarity of understanding, it’s hardly cosmetic.
The other barrier is the craft of writing. Refined writing in general requires a great deal of iterated editing, but many philosophers are also fairly talentless from a literary point of view. Most academic philosophers probably aren’t even trying to write particularly well, but to write academically.
It’s simply easier to assemble terminology that obscures meaning than employ metaphors and descriptive language so that any receptive and intelligent person can understand.