Small breweries already operate on small margins. If the big guy lowers them more it means fewer will open and more of the ones that are open sell out. Once AB InBev owns a large majority of the craft breweries what is stopping them from closing them down in favor of higher profit margins selling Budweiser, instead of costly to produce stouts, porters, ipas, etc. This has already played out once. Post prohibition when only the biggest survived, it took damn near 70 years for small upstart breweries to start gaining market share again. If Ab InBev could close them all, they would.