feel like sicilians 1 farm upgrade is almost like heavy plow of other civs...Its only sick if you open scouts.
Other builds will skip or delay horse collar entirely. FC Arena builds are an exception as dark age farms there are nice to have in general but man at arms into archers, straight archers, drush fc. All have later horse collar timings making little use of the bonus. Scouts is where the bonus shines and only matters when you reach early to mid Castle Age.
Other farmer bonus such as Franks Slavs Chinese Teutons just do it miles better early on. Sicilians are not impressive until mid game.
So from this angle they have kind of saved 100f 100w ish to delay 2nd upgrade