Ive seen 2gpw banded around like its nothing and most of the time I question what the grower considers dry.
Admittedly its partly because I haven't hit those numbers personally
However I once did a modular scrog in one part of half my tent, it was 1.5x2ft screen, that half my tent was 4x4 and had 560w of good LED over it. That little screen I pulled 9.5oz dry off and that didn't include some larf I should of pruned and binned or a good 1/2-1oz of rot I had to bin. Extrapolate that up to the full 4x4 and it gets well above 2gpw.
So I do believe it very possible, though most of what I see claiming 2gpw doesn't look to be packed in enough to reach those figures.
I know that sounds a bit flakey extrapolating it
1.4gpw I have done numerous times 1.67 was my PB.
Now im in a totally different set up and once I have a few runs and chucks done I can dedicate a whole tent (more importantly be able to access it) to scrog a few plants and see how high I can push the numbers.
Obviously though the light is not single-handedly responsible , one way or another you have to fill a space well.