escalation of the crises in Europe, which historically - see: WW2 - has massively benefited the US. more incentive to import American gas. damage Russia; the US objected to Nord Stream in the first place. also can be used as justification to increase support for what is essentially a proxy war in Ukraine
the EU/US economic stratosphere is not necessarily a zero-sum game, but in general if Europe’s economy separately takes a hit, the US gets stronger
Prevent negotiations between Russia and Germany particularly. Then sell exorbitantly priced US LNG to a captive Europe. All of which is basically happening now.
Russia benefits if they can spin it as US action, as the damage to US alliance and trust relationships are huge and definitely strategic goals and gains for them. For a while in the beginning, when it wasn't clear that a functioning (but unused) pipeline remained, Russia was off the suspect list. But it turned out the sabotage missed a pipe and that fact keeps Russia high on the suspect list.
As for US, Germany had already given in to the US pressure and nixed the pipeline and made the gas deals. Why would US go and blow it up? It is possible, but makes little sense.
Whoever did this did so knowing that US will ultimately be blamed. Biden kinda set US up for that with veiled threats regarding NS before the Russian invasion. It's either Russia or UK/Ukraine, is my guess.
Most Baltic basin states, except Germany sort of, benefit by reduced reliance of Europe on Russian gas. Russia is constantly making threats to all of it's neighbours in that region but keeps discord in Europe via the gas blackmail. Similar story for Ukraine.
Western Europe - it's also not inconceivable. For example France is a net exporter of energy to Germany, and probably also doesn't like the Russian gas blackmail (while being less susceptible to it herself).
So literally anyone has some kind of incentive. Except perhaps Germany. You could still argue that Germany benefits in the long run as that reliance is bad for them, as it turns out, but it's harder to see them going cold turkey on themselves.
