Assuming a third of Wonder's sales are digital it should end the year around 2.25 million, a fall of 25% from the NSMB Wii game despite Wonder releasing a month earlier. Even if that were 50% digital it would have just matched it despite the Switch having three times the userbase.
That's a huge attach rate drop and it might be indicative that 2D Mario will be one of the few Nintendo franchises to see a decline this gen compared to previous highs.