Russia made tons of money in past months on oil and gas due to elevated prices. Money ain't what they need desperately now, rather massive civil unrest in EU to weaken Ukraine support and punish. Those who decide have stellar-size egos which are getting continuously humiliated by recent development. Don't underestimate pettiness of a ego-maniac person who has tremendous power and thinks about themselves as somebody larger-than-life and on a life mission. Anyway financial consequences of not selling gas anymore won't affect anyhow the folks on top, and clearly russian population is just cannon fodder for them.
Its political and military move. Realistically only US and Russia have the capacity to do 3 attacks like this simultaneously. This all benefits US too in some ways, but if I have to decide between those 2 options, for me personally its a no brainer.
Has anybody checked Russian reaction? Sometimes its quite obvious from how they say things / what they don't say whats really happening and how much they actually care. For me its not easy to see this in western media and I don't speak russian to check source directly.