Zwift ramp test just said 303 (at 72kg) and Xert tells me 327 most recently. I did Alpe du Zwift at 287 (felt like high tempo) for 48 minutes.
I’m 45 now and I was a cat 3 when I left the US for Scotland 5 years ago. I’m a 3 over here now. I won some 3/4 races in the states and club races and I’ve podium’d a couple 3/4s over here. UK fields are full and stacked and I don’t feel nearly as strong (maybe that’s Father Time too).
To TMonk’s point, I’m broader shouldered than teammates, some of whom look like their hips are almost wider than their shoulders. My sprint isn’t great, and sometimes I get intimidated by the competition. All this is to say, you could do a lot better or worse than me with 300w, so hard to say how prevalent it is.