The sellers have until the promised closing date to get their paperwork together. Sometimes it is a matter of getting all those named on the deed to do a notarized signature. Sometimes it’s a matter of collecting the funds to pay off the loan (if they are selling at a loss). Sometimes the seller is away on business or vacation and can’t deal with the paperwork immediately. And sometimes it is just the finality of it all - letting go of all those dreams of future
Disney vacations.
There are consequences for backing out of a sale. IIRC, a seller is obligated to pay the commission to the agency if they don’t go thru with the sale. They may also be under obligation to pay the title agent’s fees and other incidental costs.
However, as a buyer, the only thing you get if a seller backs out is the return of your escrow payment.
There’s no harm in asking your agent to find out what is taking so long. Maybe it will light a fire under the seller to get moving. But by contract, they have until 11/21 to take care of their end.