His point was that they don't have to try to win. They just have to stay an expensive, dangerous, nuisance for long enough that the Russians get frustrated and go home.

Like the Soviets (and, later, NATO) in Afghanistan, the USA in Vietnam, etc.

That's the way almost all wars are won.

Also, even if they were to capitulate, now, and Russia could stroll right up to the Polish border, Russia can't hold Ukraine.