Looking at existing blockchains, there's the actual blockchain that you have to program, devise consensus algorithm, implement the consensus algorithm, create a software for miners to run for nodes, work out the economics of the blockchain, find people to run the nodes, then build the actual application on top of the blockchain for consumption. How does one do all of this?
To answer the question:
1. You don't really do all of this.
2. If you truly have a viable cryptocurrency/blockchain they (the people you mentioned) will come looking for you.
3. They will come building nodes for you. Using their own pockets.
4. They will transact on exchanges to keep your crypto active.
5. An active crypto attracts more users. Thereby more word of mouth.
6. You will expend less and the public will do more to expand the network. They will earn from mining.
7. The network will be upgraded by the public on the software and the hardware side.
8. Which is why it is called the public blockchain.
9. The public will demand reforms on your software.
10. You will yield to their demands
11. That is why private blockchain doesn't exist. Nobody would bother to build it.
12. The way Bitcoin and 400,000 others were built.