Vienna has said it can cope with the loss of its main gas supplier, with reserves and alternative energy sources. Austria was one of only three EU countries still getting gas from Russia
The Austrian energy company said it had expected this development and that the country will continue to get gas through import from Germany, Italy and the Netherlands.
So the reason is that they can't deliver gas beyond the first of January anyway due to Ukraine shutting down the pipeline, and due to unfulfilled obligations they wouldn't receive payments anyway, so they can shut the delivery down right now. And politically, they obviously see no harm in burning even the last few bridges into the West. Or maybe Gazprom is so broke, they can't afford it even if they wanted to.