you've obviously never seen the cn servers or hell even the na servers, mains become useless and then get reworks done to them, currently on cn fire is worthless before its latest rework water was useless as well, thats why you didn't see people playing them competetively.

water used to be worthless here in 1.0 but it got buffed alot so now its good on the other hand fire got nerfed so its the worst main in na and is worthless compared to the other 4 mains