Europe/NATO have a vested interest in keeping Ukraine fed, watered and fully stocked, as wellIt's harder as the war goes on for invading forces traditionally, especially with the economic sanctions in place.
If the people fighting don't lose hope in their cause then they won't be short on supplies anytime soon, whereas there's plenty of reports of Russian vehicles running out of diesel and having to be abandoned, soldiers begging for food and water from locals because rations have run out etc.