I think the idea behind intellectual property is to encourage people to take risks associated with developing something new and profit through their innovations. If all new discoveries were the property of the state/public then there wouldn't be a high incentive to be inventive for any given individual.
It's like if everyone was a farmer but everything harvested was immediately taken from the farmer. Why would any farmer put in effort to increase yield when they would not profit from their extra effort?
It's like if everyone was a farmer but everything harvested was immediately taken from the farmer. Why would any farmer put in effort to increase yield when they would not profit from their extra effort?