I mean, there's 650 word assignments and 650 word assignments. This one sounds like a joke but I've had assignments in science units that were around 600 words that needed to be fully referenced and to both adequately describe and comment on a complex topic, where the word count was explicitly set very, very low for the amount of evidence we were expected to provide, by a practitioner who was frankly very proud of the high level of difficulty of the unit, which was a capstone environmental science unit. He was constantly talking about how many people had to repeat the unit, "because they didn't actually complete the assignment", because it's honestly hard to know if you've gotten enough done to answer the prompt in so few words! I did pretty well in the unit overall - one of my weakest but still I believe I got a distinction - and I was sweating bullets worrying about whether or not I had adequately responded to the assignment question. Those assignments weren't especially time consuming perhaps but they were difficult.

I'll also say, I don't know if you've had to write a (scientific) lit review or other assignment for a science unit where you're providing 3-4 references per paragraph, which you should understand and paraphrase to support whatever you're trying to say, but bumping out the 2,000 words was always by far the easiest part of that process - a week and a half of reading journal articles and taking notes followed by a few hours of typing.