A front collapse can happen rapidly, as we saw with the russian front line in 2022. Russia, unfortunately, has massive military advantages over Ukraine. Ukraine is basically holding on because the people are fighting for their country, while russians are fighting either for money or to kill/invade.

Russians are slowly creeping in. I've heard ru-bankruptcy narrative for 3 years now, and it's not happening. They can buy lots of stuff with all the oil/gas/metals/minerals/lumber sales.