The case for Russian adventurism

Russia has more staying power than flaccid, energy starved west.
Putin secures Donbas, and Ukraine pledge of non-NATO neutrality.
Russian culture gets shot in the arm. Population plunge stabilizes. Vodka consumption moderates. Role of Orthodox Church strengthens. China/Russia energy ties strengthen.

Europe weasels out of overt support for Ukraine in return for energy security.

Noticeable direction of this outcome seen by 2025 if not before.