Sure I can make my own ISP. It just won't be an international network with billions of people on it. But I'll set up a server in my house with my new ebay on it and connect it to my neighbor running his new facebook. We could even do it wirelessly.

It won't be that great, because he wants to share pictures of his kids and I want to sell my funko pops, but it's definitely easy. Unless your definition of an ISP inherently includes a connection to millions of people, in which case I don't understand why your definition of an eBay doesn't as well?

That's funny because your eBay clone will have a connection to millions of people.

You also seem to forget that the "I" in ISP stands for Internet. Your connection to your neighbor is just a LAN/WAN and by definition is not an ISP.

If it's not connected to the internet, it's not an ISP.

How will you access global DNS?

Can I ask your motivations here? You seem very keen on muddying the waters in this discussion.