With 10,000 beer breweries in the US alone, Bud and Coors have plenty of competition.  Reaching customers is complicated by government regulations that differ from state to state and 3,000 independent distributors.  And what about wine and craft cocktails?  Despite all of this, Bud has 40% of the market and Coors has 20%.  It may be simpler to just focus on growing the demand for all beers and continuing to get their share of a growing pie.