I can't find any reliable reference points for console sales in 2017. VGC's estimates for 2017 are contradicted by the article's statement that shy of 2.5m in 2018 constitutes growth over 2017; VGC has 2017 above 3.1m. Another problem is that game journalism is iffy, so it can't be ruled out that the article's comparison between 2017 and 2018 only concerns PS4, XB1 and Switch while the 3DS is ignored despite wording that should include it; nevermind that "official hardware numbers have yet to come in", so who knows how accurate the article is in regards to hardware sales to begin with.
In any case, there's too much guesswork involved to discern the sales of the PS4, XB1, Switch and 3DS in 2018.
Another unreliable source of information then...."surprising".