To many, the late 1960s marked a high point in American drum corps activity and participation. At this point a group of a dozen or so managers and directors of the higher-scoring corps of the era met to organize a by-invitation-only cooperative group that took on the working title of "The Combine". The Combine's member corps all agreed to demand, starting in the 1970 competitive season, a fixed and predetermined appearance fee from contest sponsors where Combine corps would compete, rather than accept traditional prize money awards dependent on contest placements.

Contest audiences of 1970 also noticed that some Combine corps were attempting "Total Programs" - a phrase describing daring, controversial theme-based competitive innovations in costuming, marching and music that were clearly different and more radical than the then-standard norms.

From the Combine soon evolved the more structured, open-membership Drum Corps International (DCI). The first DCI National competition was held at Warhawk Stadium at Whitewater, Wisconsin in August 1972.

Beginning in the early 1970s, many corps chose to become members of DCI or DCA (the "modern" drum corps organizations), often driven by the withdrawal of support by their traditional veterans-group or church sponsors, although it must be pointed out that by this point in time, the traditional sponsors were in many cases already withdrawing their support of the activity. The increased requirements of time and money to participate in DCI and DCA circuits proved prohibitive for many non-profit organizations with other primary missions. Groups without adequate funding did not survive. Many other groups chose not to move to the new style, citing tradition or principle. It was at this point that "classic" and "modern" drum and bugle corps became two very different activities.

Since the mid-1980s the classic "Golden Age" drum corps movement has continued to grow with approximately forty such American corps currently active; these have lately become known as "alumni corps" whether or not the majority of the membership is indeed a veteran of the Classic era.

Most current classic corps are intended to serve as tributes and to remember the heritage of the Golden Age. Even so, they still are usually made up of people from a much larger area than the immediate city each represents.

The main Classic corps organization is the East-coast-based Great Alliance Seniors (GAS). Forsaking competitive judging, the GAS-affiliated corps meet to rehearse, socialize, and perform to parade, standstill and field-exhibition audiences.