Bitcoin is the incentive to keep the Bitcoin blockchain secured. Without that incentive there would no longer be the trust factor, the network would have lost security.Imagine a centralized blockchain, where trust would be in hands of a few individuals or institutions. What if the private keys would be compromised? The entire network would have lost all value.Plus, trust centralized would be business as usual. It would be similar as the trust we are supposed to have in banks and authorities.
Bitcoin was designed to move away from the trust through institutions to trust through networks.