Believe it or not, it's pretty hard to conduct a large-scale study in the middle of the largest pandemic in modern history.
I mean, that plus Zoom and you're like halfway to a world-wide sample size, more-or-less
On a serious note: I'm extremely grateful for everyone who's working to solve this big and complicated problem, and (like the other poster said) it's entirely reasonable that it's really difficult to get larger studies going.
A bit of self-promotion: https://news.ycombinator.com/item?id=22787162
In fact, I am impressed, this is not a thing yet.