I agree with the fact that businesses don't like to publish - but if such community is built the businesses will be benefited more than everyone.
1) They might get better bug reports and be able to fix them better, giving a less buggy product and making them better than B - good for A
2) A user reviewing both A and B might see that A has a list of bugs, and (most likely mistakenly)assume since B doesn't have such a list that B has no bugs. They assume B is better - bad for A
I suspect it depends on a lot of other factors which of those results is more pronounced, but it is unproven which way it would go for any given business.