One replacement source for those nations cut off by Russia or voluntarily banning imports of their petroleum products.
The countries involved with the Nordstream pipeline had believed they were doing something that would help Russia’s economy (and it would have, at least where oil and gas was concerned). In this, they believed Russia would become a better neighbor and not one that would abuse that partnership. Now that they see Russia as an abusive partner, they are smart to rethink that and make sure they are never fully dependent on it. I’m allowing that it could be realized in the future, but after Russia gets rid of it’s dictator and gets their oligarchs under control.