Yeah, I’m just trying to come up with a playable system for my roleplaying game campaign. I want to be able to use the SFTM as a more-or-less reliable resource for my game, but if a year is about 1,000 stardates, then it looks like Starfleet was commissioning dozens or hundreds of ships every year. That can’t have been what FJ had in mind, is it?
The "1000 stardates per year" formula wasn't invented until TNG. So naturally nobody creating Trek-related material in the 1970s would've been aware of the concept. And it probably didn't apply in-universe either, since if you project the TNG-era stardates back, they reach zero in 2323. So the stardate system used in TOS can't be the same one used in TNG.
The one and only purpose of stardates in TOS was to convey no actual chronological information of any kind. Roddenberry wanted to be vague about how far in the future TOS was (so that his predictions of the rate of progress wouldn't seem either too optimistic or too pessimistic), and about how much time passed between episodes (since there was no way to control what order the network showed them in), so stardates were just numerical
lorem ipsum, intentionally meaningless placeholders just conveying the vague impression of being a dating system. There was a loose, general upward trend in the numbers over the course of the series, increasing by nearly 2000 units from the beginning to the end of the first season, about 1700 in the second, and about 1500 in the third, but nothing more consistent than that. (For that matter, if you project them back, then they must've only just started the calendar less than a year before, since it starts at 1312 in the second pilot.)
And there was no evidence that a season's worth of episodes actually lasted a year in-story anyway, since shows back then tended to be deliberately vague about the passage of time (e.g.
Run for Your Life, a 3-season series about a man with 18 months to live, or
M*A*S*H, an 11-season series about a 3-year war). TOS episodes rarely referenced previous episodes, and when they did, they never specified how long ago they happened.