There are limitations on how much he can spend prior to becoming the official nominee. After the convention, look for a huge media surge.
I don't believe it's the amount of advertising that is questioned as much as the content. How much does it cost to take punches at JugEars during fund-raising speeches and interviews???
Romney hasn't landed a single punch and any damage to Obama has been self inflicted and it should be obvious, even to a straight laced Mormon that you don't win a boxing match by hoping your opponent knocks himself out but that is the pattern that's developing.