It's a strange feeling if you don't get anything after mining bitcoin especially if you start from 2015. There might be something wrong with your bitcoin mining, because as far as I know there are 2 types in the bitcoin world.
1. Miners
2. Traders (people who buy and sell bitcoin)

The function of the miners is to validate every transaction and secure the Bitcoin network. They perform very complex cryptographic tasks to create new blocks in the Bitcoin blockchain. In addition to speeding up the bitcoin transaction process from one account (Wallet) to another wallet. It's easier like an interbank transaction, this miner will get a fee for every transaction from the customer. So it's impossible for miners not to benefit.