I don't think Ukraine can beat Russia in a regular war and has to eventually shift to full guerrilla warfare, with which the Russians would have to deal with for years.
Some in the Kremlin might have expected the takeover to be as swift as the Taliban taking back Afghanistan with little to no resistance, before other countries can agree upon any sanctions or reaction. If that were the case, I think sanctions from the west would have been much tamer, due to the war already being over and less political pressure from their own constituencies. E.g. German government needed at ton of public outcry first, before they changed their mind.
Also the longer it takes, the more Putin has to deal with opposition in their own ranks and populace.
Some in the Kremlin might have expected the takeover to be as swift as the Taliban taking back Afghanistan with little to no resistance, before other countries can agree upon any sanctions or reaction. If that were the case, I think sanctions from the west would have been much tamer, due to the war already being over and less political pressure from their own constituencies. E.g. German government needed at ton of public outcry first, before they changed their mind.
Also the longer it takes, the more Putin has to deal with opposition in their own ranks and populace.