It would be misleading to say that only a majority of academic writing has unnecessary use of long words because this is almost universally true. I would guess that it's north of 90%.

You talk about making no assumptions. I agree that this is excessive, but why can't an MSc within the relevant area be enough? Yes, you save some space by using a lot of jargon, but if you use a word only once in your article, would it kill to spell it out instead? And while jargon occasionally saves space, snobbish language never does.