Research and clever marketing.
BMC has designed a beverage that is least offensive to the widest audiance. Think about who likes your home-brew. Some love, while others don't. Think about a particular style, ipa vs porter vs belgian. Big bold differential flavors that appeals to some but repulses others. Big bold flavors are great, assuming they meet the audience, but the more flavor you add, the smaller the audience becomed.
Then comes marketing. Marketing oftentimes assumes/believes that the end-user is too dumb to think for themselves so they tell the end-users what they really want or think. Sadly, they are correct, we are dumb at times. How many times ave you heard someone parroting an advertising campaign opinion as fact? (Every election!) Choosy Mom's choose Jif, America's best (insert brand) and remember, This Bud's for you.