Sure it can.
There are already many You Tubers creating their main income with YouToube.
There are many different ways to earn.
The most common way is to get YouTube monetize your YouTube Videos.
You Tube will then display Ads before or while your videos.
The ads are paid very bad so you need a lot of views on your videos.

A other way is do ads by yourself. For example for Amazon. You will get paid everytime someone buys a product with a Link that you shared on your YouTube Channel.