I checked the issues of Star Trektennial News, the Susan Sackett-edited newsletter that ran in 1976-1977, to see if there was any reference to doing the Star Trek revival as a “wheel” series. But by the beginning of 1976, when STN was launched, the chatter was about the upcoming movie that was to start shooting in July, 1976 even though there was no script. (July slipped to September, then November, then mid-1977, then off the schedule as the right story failed to materialize.)
There was a comment in the second issue of STN (issue 14, because they continue the numbering from the original 1968-1969 Inside Star Trek, which ran for 12 issues) that “we are hopeful that there will be television 120-minute specials once the movie is a success.” So the idea of doing more Star Trek TV movies after doing a movie-movie was definitely being discussed.
I recall reading somewhere about 8 Star Trek TV movies per season, but I can’t find it. I don’t recall ever reading that they would be part of a rotating group of series. I always assumed they would be once-a-month standalones — but whatever network aired them would have to schedule SOMETHING between treks.