Tether owns in excess of $1 of assets for every tether outstanding.
You have no proof of that, because they have never submitted to an independent audit. You only have their ever changing word to go on, which is worth nothing.
I don't think their word has changed. If you are going to assume their word is worth nothing, there isn't much of a point even discussing their situation.
The NYAG did not explicitly say this, but it appears they verified tether had $1 in cash-like securities prior to giving the loan to Bitfinex for every USDT outstanding. I believe this because the NYAG is very anti-business, and would have pointed it out if there were not cash like reserves.
Your bank account is also backed 1-to-1 with reserves, a small percentage of which is cash like assets, and the majority of which is made up of loans made to various customers.
But again, Tether isn't a bank. They widely and very specifically claimed that USDT was backed up 1-to-1 with USD, which they've now admitted was a blatant lie. "Cash like assets" means nothing, since they include other cryptocurrencies in that definition. If they print a hundred million Tether out of thin air and use it to buy Bitcoin, they can claim that Tether is backed up with "cash like assets".
I don't think "cash like assets" would include bitcoin in their definition, nor do I believe they are holding anything like bitcoin as part of their reserves.
The claim the USDT was backed 1-to-1 with USD was not a lie. The claim was changed to its current form at the time they made the loan.
Your bank account is also backed 1-to-1 with reserves, a small percentage of which is cash like assets, and the majority of which is made up of loans made to various customers.
It boggles my mind that people consider outstanding loans to be a form of backing. You no longer have access to these funds. All you are left with is a contractual agreement that the loan will be paid back with x percentage of interest. If every Tether holder will be looking to cash out right now, they can't.
If you have a bank account with $100 in it, your deposit is exactly as you describe.
If you have a bank account with a billion dollars in it, your bank will almost certainly make you wait seven days (they may delay further) to process a wire withdrawal of a billion dollars. A bank deposit is not backed 1-to-1 with cash by the bank, and will need time to liquidate cash if a customer is making a very large withdrawal.
I speculate most of the other stablecoins invest most of their money in short term US government debt securities verses a bank deposit.