Things change. It is foolish to imagine Russia's reach would remain unchanged when it now controls 2% of world GDP while it used to control more than 10x that amount.

Certainly Russia will not like loss of control, and certainly if the west were to make use of this new power to blockade Russia without provocation, it could lead to dire outcomes.

But consider the case of Crimea. Why did the west 'allow' this to happen? because it was within Russian sphere? I submit it was mostly because the west was powerless to stop it. (without nuking someone, or a MASSIVE military buildup to retake it.)

But as Russian ability to project power is diminished, its ability to force outcomes will also be diminished. Just the possibility to enact this blockade will notably limit Russian adventurism.

It does seem the west miscalculated when it publicly acknowledge plans to integrate Ukraine many many years before such an integration was going to happen. If we had known what Putin would do we would not have said it. Maybe Putin would have attacked anyway, it is now impossible to say.

And Putin miscalculated too. If you look at Ukrainian support for Russia, it dropped massively after crimea, and even more now. They have lost Ukraine even if they clawingly hold on to part of it for some years to come.

big miscalculations on both sides.