Going back to the territory years, I think it could be divided into a few distinct eras.
-Early Territory Era (1956-1963) Vince Sr starts promoting in NYC that year, and many of the classic territories TV shows begin their runs (eg. Wrestling at the Chase) and/or start promoting (eg.the AWA). 1963 sees the start of the WWWF and the end of Buddy Rogers mega hot run.
-1960s Slump (1964-1969) Business drops off in a lot of areas during this time, and wrestling is generally not as hot than the era before or the one that followed
-70s Boom Era (1970-1975) Hot period that featured most territories doing great, often record-setting business. Mileage varied from territory to territory. Some had declined greatly from their peak by 1975, others (WWWF, Carolinas, Florida) would continue to be successful throughout the 70s.
-Late Territory Era (1976-1983) Several territories died during this time, including SF, LA, Detroit, and Amarillo. Vince Jr buys the WWF from his father and his partners in 1982. Business in many NWA territories was record-setting in 82-83.
Of course several territories continued after 1983, but 84 saw the beginning of Hogan's run as king of wrestling and the WWF's aggressive expansion into other areas.