You have a good point in that "there isn't anything in it for them" It's too bad for the smaller company's that could use the help of a direct comparison to justify their worthiness of market share. It's too bad for the big company's that crunch the numbers and realize there is no benefit to substantiate there existence with any kind of truth in advertisement. The few things that could be of interest to a larger company would be bragging rights, not only against a group of smaller manufacturers but if you got all the sub guys to show there face, there would be a comparison across a larger group that the buying public is looking for. If big boy ultra expense products came out on top it would be more proof on their part, that if you want good equipment the DIY rout is not as good as spending lots of dough.
But.... I see your point because I don’t have any need for advertisement myself. The effort just doesn’t pan out to be worthwhile.