The Wisconsin Hospital Association report last week that projected a shortage of almost 2,200 physicians by 2030 drew attention to an escalating problem: The United States is training too few primary care doctors. The hospital association estimates that primary care physicians - doctors who specialize in family and internal medicine and pediatrics - will account for about 80% of the projected shortage. It works out to an estimated 1,767 primary care physicians - or enough doctors to provide care for more than 3 million people. The state now has about 6,000 primary care physicians, some part time. Projections on the supply of physicians have often proved inaccurate. But no one questions that the country faces a growing shortage of primary care physicians.