Complex sentence: The momentum did not last as Vargas, Avila, Mendte, Stafford and Stensland all left the station within a short time; by the mid- 1990s, however, WBBM-TV had fallen to last place.
Split into simpler sentences: The momentum did not last as Vargas, Avila, Mendte, Stafford and Stensland all left the station within a short time. By the mid 1990s, however, WBBM-TV had fallen to last place.