Of course they have the ability, it's called time. No country can afford to wage war for decades, especially an imperialistic war under sanctions. Even if the western countries completely stop their support and the conflict would freeze, Russia can't stay indefinetely in Ukraine and lose daily men and equipment. Ukraine on the other hand fight for their independence and surviving, they will do this indefinitely, no matter the cost. There will come a day, when Russia must say enough is enough. Is it next year, in 5 years, in 10 years? This will depend on our support. Putin has lost, the question remains when.