[thinkmassive]

The block reward halves approximately every 4 years, and it's currently halfway through the 12.5 BTC reward period. Based on this schedule there will be a mining reward until the year 2140.

In addition to the block reward, the miner who finds each block also gains a fee from every transaction in that block. Ideally this fee stays low, but it depends on network congestion (and what miners are willing to accept, since they choose the transactions that make it into each block). The transaction fee has already hit the equivalent of $50 per transaction, back in late 2017.

Even with improvements such as batching, segwit, and lightning, there is still likely to be sufficient returns to incentivize miners for the foreseeable future.