The first is by owning a portion of the tokens. When a blockchain application does an ICO, their tokens will have a determined value, and if the company owns, for example, 20% of the outstanding tokens, it would be value to them that could grow linearly with their company or product's growth. This type of model is adopted by anyone who issues their own token but its sustainability is not yet fully known.
It may be that blockchain companies/applications/platforms must have an associated fee for their services. Bitcoin's miners won't make anything around the year 2140 once all coins from the reward pool have been distributed. Fees are necessary to provide the incentives to the miners that still support the system. This applies to any blockchain application.
We'll soon see innovations not just with blockchain applications but also their business models in the coming months/years.