The people whom A/B testing can help are running sites with million of hits.
Using data to test product iteractions, interface changes and catch low hanging fruit is totally standard and widely practiced. Companies not willing to use data driven measurement are lagging behind by at least 5 years.
It might be a scale issue for sure, but qualitative data alone is not enough, especially when dealing with user biases and small, non representative populations.
Many, many sites with millions of visitors are not yet A/B testing. Vastly more than you would think.
The sites with millions of hits not A/B testing might be helped by an A/B test but more likely will just chase ghosts and give it up.
Or they could just hire a good UI/UX and conversion expert and get the insights for free.
Take agriculture - you are running a large farm which is hundreds to thousands of acres. Do you run experiments with soil, seeds, fertilizer, crop rotation schemes to increase yield? No, that would be silly, take forever and make you poorer and perhaps no wiser. Instead, you hire a "expert" who has done it before and knows the "best practices".
