Does anybody here understand what these scientists have supposedly achieved?
This is in my area of research, and I read and understood the abstract. It does not seem like something that should be posted on Slashdot.
In this case, quantum fluid means a fluid that is cold enough, dense enough, and made of low enough mass particles that it has some quantum mechanical properties (interference is an example in the abstract).
Making a bigger quantum fluid is not really a challenge - you just need a bigger refrigerator and a bigger tank of helium. In this case, they made a bigger quantum fluid of a very specialized type.
But isn't the whole point to quantum science that observation collapses a state into one thing or the other?
No. That is just one small part of quantum mechanics.