No it won't run and run since Putin isn't going to be staying in occupation of Ukraine. He isn't even going to attempt to occupy all of Ukraine. All he wants is the eastern two oblasts of Donbass (which are 100% Russian anyway) and a land link from there along the western flank of the Azov Sea to separate the Crimea from Ukraine.And in mean time Ukrainians are dying along with Russian soldiers. This isn't like the past Flecc when Russia rolled into Hungary. Ukraine is 10 times the size and Russia nowhere nearly as powerful as in days gone by. Agreed short term victory will undoubtedly go to Russia but this will run and run. Ukraine will when defeated fight a Guerilla war, Russia hasn't done well in other countries under such situations and this time its agianst their own. Help will be flowing into Ukraine both now and for years to come. Its the very nature of Russia's weaker position that makes situation so much more dangerous and exactly why it could escalate. Ukrainians do stand a chance, and will not accept retrograde steps. If they don't succeed now, they will fight on and on. Nobody knows where this could end. Putin has gone in not knowing the end game. Always a recipe for bloodshed.
On the map below he's effectively possessed Russian populated Donbass for a decade anyway and Russian populated Crimea since 2014, so all he needs to gain is the red hatched area to protect his Crimean based southern fleet. That's a minute part of Ukraine, but once he has it he can withdraw and leave the Ukrainians alone.
It will be a repeat of his withdrawal from Georgia after he'd completed what he wanted there. Then he'll agree with the outside world's requests to withdraw, thus showing himself to be a reasonable person after all.
Never ever underestimate Putin: