...No, the existing armies of the world make it possible. Why do you think Coinbase, Kraken, etc, are in the US and not in Somalia? Hint: it involves a police and an army.
You are talking about centralized exchanges, which is something built on top of Bitcoin - much like the current banking systems. You are not required to use that with Bitcoin. With Bitcoin someone anywhere can have a "bank account" where the asset doesn't loose its value based on local circumstances.
I assume you argue that a single army/government could take out/control miners - which would be the better discussion to have. That's where we would talk about the value of the Bitcoin network.
No, I mean that bitcoin as a whole would be back to 2010 values should these exchanges not exist. The only reason bitcoin has value is that leeches decided to speculate on it, and leeches need a centralized exchange.
Centralized exchanges are the reason you don't pay 10000 bitcoin for a pizza. They're the reason why it's even accepter, because there's at least one large place that will exchange your coins for cash.
Calling Bitcoin owners leeches seems a bit of a stretch.
In my opinion there is little to absolutely no reason to ever change Bitcoin back to cash. Maybe take a loan against or rent it out to others for cash interest, if you really want cash.
I don't need a bank. I choose to use a bank for the services they offer. Switching currencies doesn't change this, I will still use a bank and a financial system. So bitcoin only helps me if customers are paying me in bitcoin.
I don't value trustlessness, and in fact lack of trust is a vacuum filled by evil.
Of course not. The existing ones you depend on to protect the necessary infrastructure and servers of bitcoin are already sufficient.