It's not the same thing. We aren't talking about just one pilot movie or a source theater movie like "Baby Boom". Nor are we talking about pilot films that showed up on the ABC Movie of the Week like "The Immortal".
The Immortal (TV Series 1969
We are talking about "shows" that were being done as a series of movies or two hour episodes and then some executive decides they want it as a weekly hourly show.
Kolchak consisted of two movies, "The Night Stalker" and "The Night Strangler". There was to be a 3 rd movie, "The Night People" but it went to a TV series and died within a season.
"Man From Atlantis" was 4 movies before it became a series.....and died with a season.
Battlestar Galactica had the first movie, then it had 2 hour specials like "The Tombs of Kobol" and "The Gun on Ice Planet Zero"....but then they wanted it was a weekly TV series so in the scramble, episodes like "The Lost Warrior" were produced.
It would be like taking a character out of the NBC Sunday or Wednesday Mystery Movie, like McCloud, and making him instead a weekly hourly TV show.
As it is, I recall, there was one show at least they did that to, "Quincy" and it did last more than one season.