Whatever the cause for melting Arctic is, it's actually bound to cause more use for those icebreakers instead of freeing them up. Just like any other country with coastline to Arctic sea areas, Russia has plans to drill oil in the Arctic. They are also trying to start using the northern route for shipping around the continent.
Also as previous poster noted, there's always winter. And it's not necessarily getting any easier because of the global warming, because extreme weather conditions may become more common.