GeForce NOW is also an option for those who can't update.
Yes, I hear good things about this for folk who don't have a good enough PC but do have a good internet connection.
From what I understand, GeForce Now is more flexible than Stadia was as you can use your Steam copy to play either on that or on your own machine. Is that right? It looks like free access to GeForce now is pretty basic with only 1h sessions, but seems a great option as a temporary way to at least be able to try the game out and decide whether it's worth splashing out on a pricier monthly GeForce Now subscription or a new machine to keep playing.