Sure, that's why I used the word theoretical myself, but my hunch is that it's not trivial for the reason that it's a really tiny basket of goods we're talking

Sure, that's why I used the word theoretical myself, but my hunch is that it's not trivial for the reason that it's a really tiny basket of goods we're talking about. I even think it's not trivial if your market is restricted to say, 25% of the general market. But in this case the restriction is to a tiny percentage of the complete basket of goods, so (as an amateur) my guess is it's significant.