Also, miners might start to supplement their income by hosting LN Nodes and getting fees from forwarding people's tx's.
The good thing about the LN is that anyone can open a big amount of channels to get payed to route a payment.
You don't need specialized hardware and electricity costs far below the average to compete and earn money.
You just have to provide a funded channel to route the payment. So anyone (including miner) can participate the same way.
Lightning Network earnings are quite small and might not be worth the hassle of balancing thousands of channels.
They are small (or non-existent) at the moment.
But once LN is 'released' and truly tested and fully developed, the fees will increase when the user base and transaction made there increases.
These tx fees will still be way lower than the fees from on-chain tx's, but balancing thousands of channels should definitely make it worth it (at a stage where the LN is fully functional and used).