Where are you pulling that from?
In 2013, the PC market had revenue of 531 million, all consoles combined only 862. And there isn't a console that dominates with more than 50%, so obviously PC #1.
This always brought up in Germany sales thread. Here is the thing: PC has been the strongest platform if you compare it to other individual platforms in the last years. The time where PC was bigger than all consoles combined is long gone.
Sony announced mid-last year( I think it was on a SXW panel), that for the first time PS4 was the strongest platform and beat PC.
You can see this also from the revenue chart 2014 from BIU as PS4 has probably 50%+ marketshare.
However, pc titles sell for less (new pc titles 40-45€ , new console games 55-65€
. On average it's even more drastic. PC titles sell for ~22€, console titles for ~48€ (from my memory - didn't look it up).
Regarding shelf space (has already been said, though).
There is the hidden object section, a lot of german only adventures and sims, a lot of german only pc collections (adventure pack for instance) and green pepper section (another budget section with a special label).
Those titles may not sell much individually and we don't see them in the charts, but they add up. Charts are only Top 50 or Top 100 - we would need Top 500 to see those PC titles.
Green Pepper for instance (all games are 6,99€ they usually have 50+ titles in the store):
https://www.greenpepper.de/charts/
There is also a another budget section which mostly consists of PC titles, as media markt/saturn usually uses promotions to clear console game stock (besides Softwarepyramide - another budget section that includes pc+console).
Picked up LA Noir complete edition for 10€ yesterday. Pretty much the whole year you get better deals in retail than on steam. And new pc titles sell for 15€ less than on steam.
Regarding games sold and revenue (this is from 2013 and includes retail and digital):
In the category games sold PC should still be the biggest platform (and that's the reason why it gets so much shelf space). Revenue is obviously more important - so PC isn't number 1 anymore.