A healthy hive would get proper nutrients. Usually you only need to feed a hive pollen when it is a weaker hive that doesn't have the population needed to collect pollen. This boosts brood production and the hive can recover faster.

Another issue is commercial beekeeping. Hundreds of hives could be working a few square miles while in nature it would be just a few. Not enough resources for that many hives so weaker hives struggle. This is a human solution for a human problem.