Buying and selling restricted to those with the Mark

Ever wonder how the entire world could ever evolve into a one-world economy where buying and selling is not allowed unless you have the Mark? Especially when we Christians have been warned of it ahead of time?
Let me tell you how I think it will play out.
First, most countries will go to a national banking system. Just read the news and you can see how America is currently on track to do so.
It is no secret that China is heavily invested in America's debt. When America defaults on it, they will no longer be the global superpower. Then the global economic crisis (GEC) will require other governments to bail us and China out. Once all banks are intertwined in debt, everyone owes everyone else and certain countries currency will be worthless. People will be begging to have a currency that is worth something, so a global banking system will be created, all connected by the net. Countries like America and China will probably start doing business with the Euro.
Meanwhile, profit margins are squeezed so tight by the GEC that companies everywhere will have to slash their costs. They will turn to technology. For instance, instead of having a checkout person scan groceries, you can simply walk out the door with whatever you want. No clerks. Whatever you are holding is automatically registered at the exit and charged to your accounts (all via RFID). But wait! What if someone comes in the store without an electronically RFID'able account? They could steal stuff since no or too few employees are around to catch them. So therefore in order to get through the door, you will have to have an account (preferably with credits in it).
Likewise, the banking industry will make their deals more efficient by gradually having everyone switch to the same electronic currency. There will be bank mergers and closings as all banks become identical (thanks to Off the Shelf IT solutions), and therefore redundant and unnecessary. Eventually there will be no private banks, and only a few national ones. Then two national banks, then one.
In these times of desperation and economic and political collapse, there will be a lot of people doing whatever they have to do to not starve. There will be account/identity fraud galore. The only way businesses will be able to combat it is to give every person a personal identification account number that is encrypted and cannot be removed from that person's body. This is possible due to the quantum cryptography some governments and companies are now developing. Imagine a cluster of molecules implanted somewhere in your body (no one knows where exactly). They are split in half and the other half is sent to the central bank. But these are special molecules. Whatever happens to one in one half happens to the other. And it constantly transmits via electrical impulses within your body, your ID number to an RFID chip on your skin, which has a battery and can transmit your ID number when you walk into a store.
And Voila! You now can't walk into a store without having an account with that one bank.

The good news?
This will take a while to implement!