I don't buy that explanation - there's also just a lot of bad writing out there today. And, I'd wager, you'll find (more frequently than before) attempts to impress (and even obfuscate), rather then communicate and elucidate.

Note also that your hypothesis was briefly addressed in the article:

> An alternative explanation for the main finding is that the cumulative growth of scientific knowledge makes an increasingly complex language necessary. This cannot be directly tested, but if this were to fully explain the trend, we would expect a greater diversity of vocabulary as science grows more specialized. While accounting for the original finding of the increase in difficult words and of syllable count, this would not explain the increase of general scientific jargon words (e.g. 'furthermore' or 'novel', Figure 6B). Thus, this possible explanation cannot fully account for our findings.