What other ways are there to acquire knowledge? Will the Internet be helpful?
If you want to learn the basics of any topic, Wikipedia is a good starting point, although not a sufficient ending point. Check the sources referenced in a Wikipedia article if you want to go deeper in a topic.
For current events, read the newspaper. Online newspapers are fine, but you need to check the same story in different newspapers or TV channels to get a sense of the writers' approach and agendas. If a news story sounds too strange to be true, check what source is quoted and search for it in other newspapers.
For very niche topics (for example, how to make your own yogurt, or how to braid your horse's tail), there are thousands of YouTube channels and podcasts geared toward narrowly specific audiences.
To learn about people's experiences, talk to people.
Besides factual knowledge, which can be gained from Wikipedia, the news, or non-fiction books, writers especially need experience of life. How else are you going to write about people, their personality, and their behavior, if you haven't gained a wide variety of experiences with people?
Hemingway was a great author because he had been out there right in the middle of things and had seen and had things happen to him. He knew the human condition and was able to write about it. And that is why most first novels aren't published by teenagers but by writers in their fourties and fifties.
So what you need to do if you want to gain non-factual knowledge is go out and live life. Exceptions notwithstanding, the most successful writers have not led a cloistered life.