The brewers are not the ones making the decisions, career executives with no background in the actual brewing process are.
This is exactly what is going on. Go look at InBev's corporate "Who's Who" (http://www.ab-inbev.com/go/about_abinbev/management_structure/who_is_who.cfm) and find one person there that has brewing education. The closest you will find is the Chief Supply Officer.
It is not like this makes me want to boycott InBev. They are a company trying to make money. So what? But, I will not simply buy their product due to some loyalty or nostalgia. If it tastes good and continues to taste good, I will buy it. If not, not. In capitalism, that is the role and the right of the consumer. If people stop buying, you fix the problem or die.