Not to rehash all these lumpy heads. I have been playing RPG’s since 1979 and played so many systems I have forgotten more than I remember I think.
Any system is agnostic to campaign length. It is what you make of it. I introduced my gaming group to ICRPG with a 5 room dungeon (I posted here on this forum). We had so much fun they wanted to keep playing. So a few random encounters and some experimentation, 8 months in we played the first Age of Snakes session last week.
I think it is unfair to make a generalization about any system. I think ICRPG’s simplicity lends itself well to one shots and introduction to the rpg world, I think that is more a function of speed of character creation, but there are no barriers to long term campaigns.
Some of you older lumpy heads like me might remember TFT (The Fantasy Trip and Wizards). That system was D6 based and you only had three attributes STR, Dex and Int. And each book was a 20 page pamphlet. Back in the day, we played a two year campaign.
At the end of the day, create collaboratively with the players and have fun in the system that gets you there.