I think the middle-ground would have been TV-movies, kind of like what they eventually did with things like the Perry Mason reunions. A series of movie-length stories with larger budgets than individual episodes and fewer total stories per year, therefore cheaper than a series overall. So you get more of an epic sweep, and more than just a movie every couple of years. The 80s were definitely the decade for miniseries and things of that nature. Stuff like The Thorn Birds and Winds of War were not cheap to produce, but highly successful, and the original Battlestar Galactica pilot was very highly rated.