The root cause is that naval warfare has practically no role in national security and hasn’t in a long time.

Even ignoring nuclear weaponry and mutually assured destruction, ships are expensive and fragile. They are easily destroyed from above or below, which makes them only useful against nations that don’t have modern military technology. If you need a floating platform to fight Houthi rebels they’re useful, if we’re facing an actual invasion they’ll be worse than useless.

As a result there’s not much pressure to get it right. If breaking ice were an activity that our national security relied upon I have no doubt we would be building them quickly.