Short answer, yes.

Literally, only two scenarios will occur, based on two assumptions.

Assumption 1, Bitcoin supply will not be increased, therefore capped at 21 million.
In this case, miners will have to rely on transaction fees in order to maintain operations of the blockchain itself.

Assumption 2, Bitcoin supply will be increased, therefore is not capped at 21 million. Let's imagine the protocol of the Bitcoin is essentially changed via consensus and allows more Bitcoin to be mined. Therefore, theoretically, miners are still able to continue their operations as usual.

However, assumption 1 is most likely to be true. This is because Bitcoin is dubbed the digital gold. The direct increase in Bitcoin supply would essentially brings harm to the financial ability as well as reliability of Bitcoin being a decentralized cryptocurrency. Because, if that's the case, what sets Bitcoin different from fiat basically would not exist anymore. So, maybe, however with large possibilities, if assumption 2 occurs, it would not be profitable anymore.