The author is wrong that Google and Microsoft don't do this level of illustration - they do and have for a while. They just do it on their home search screens, not on their App Stores
Do you have some examples? I have not encountered either. I'm familiar with bing showcasing interesting photos, which is fun, but not at all comparable to an editorial team commissioning graphical illustration for their content.
Just to provide credit; I believe the sole photo in that entire set was taken by Cole Wilson. Not %100 sure, but it wreaks of his style and composition.
Apart from including publisher results in a way that doesn't differentiate those results from apps themselves (a different icon would really help), I really can't say I have any complaints with search. That said, I tend to know the name of the app I want, rather than searching for apps with certain features, so in most cases I'm doing a very basic string match search.
I expect that Apple's approach to curation and discovery helps somewhat lessen the need for better search.
Atari box art told a story the cartridge just couldn't deliver.