We don't know what it takes to be a Fortune 500 Company. Unfortunately, we can't help you if your aim is to become a Fortune 500 Company

What we can tell you is that this market (Publishers and Books and Services for Authors) is quite well suited to making good amounts of money. However, as it currently exists, it is not suited to becoming a Fortune 500 company for the following reasons

1) It just might not be big enough. We anticipate that Services for Authors will grow to be a $100 Billion a Year Market. You would have to become one of the very biggest companies in the space to become a Fortune 500 company - that is very hard to do because no one knows quite how the market will evolve

Please Note: At the same time, this is a very good ecosystem in which to build a revenue base and a strong medium size business. Then to expand into some other, much larger ecosystem, selling similar services and products

2) The existing large companies are very focused on preventing anyone else from flourishing. This is not an ecosystem with companies like Microsoft or Apple that are looking for partners and are OK/Happy that everyone benefits
The large companies in this ecosystem want everyone to remain tiny and powerless. Instead of win-win mentality they are fixated on - We Win and Everyone Else Loses
You don't just have to run your business and be successful, you also have to avoid the large companies in the ecosystem. They are trying very desperately to keep control of the ecosystem by destroying anyone who is growing fast and/or becoming self reliant

3) The ecosystem is in a state of chaos. It is hard to say what the stable state would be. You might make the wrong assumptions and end up creating a product that in 10 years has no relevance

4) There are lots of other markets where people are much much easier to work with

5) There is very little defensibility in this ecosystem. A mixture of the constant changes in the ecosystem and the lack of companies with win-win mentality means it is hard to defend a business that you build
There will be companies that will go after you, because of their own fears of what the future might hold. You build a successful business and for them it is considered a threat because ANY successful business might become the one to take over the entire ecosystem

While there is the tremendous upside that an early start would put a business in prime position to become a very large and successful business

There is also the considerable risk that the ecosystem might evolve in strange and unpredictable ways, wiping out many existing and many new businesses

If you are thinking Fortune 500 then you would be much better off choosing one of -
1) A large established market in a stable state
2) A new emerging market that is not controlled by anyone, and where the large companies are not homicidal in nature