He got the GDP numbers wrong. Change the "billion" to "trillion" for CA, NY, and TX, and "million" to "billion" for FL. Just checked several sources, they all disagree with this video.

Edit: forgot NY

Each state in the US already is their own country. That is why they are called "states". The US is a confederation of Independent States. The Constitution called for a weak federal government which only provided for the common defense and regulated interstate commerce. Everything else they do is an abomination.