Statistics like this never paint the full picture.
For one they obviously include digital only games which is on the rise due to indie style games as well as ports of past gen games releasing only as digital options.
Secondly, its good to know physical sales this gen vs previous gen. The way I see it is overall software sales have increased exponentially this gen vs last (at least for Ninty and Sony). So if previous gen digital was 30% and this gen its 50% its doeant mean physical sales have gone down, at least not by much.
And the past couple of quarters have been affected by COVID