I know a more likely scenario: it will not improve. Switch online is literally doing everything worse than the Wii U online service. Where is Miiverse? Friend messaging? Normal voice chat? N64 games? Hell even Wii had N64 games! Nintendo had 1,5 years to come up with a decent online service. Even if Switch online was free it would still be a laughable service.
But since everybody is going to buy it anyway to play Smash, Nintendo will think they did a good job and keep it as it is now.