Ghosts isn't number 1 and has never been number 1 anyway looking at the worldwide charts last year and this year so far.
Titanfall is number 1 in 2014 and Infamous 2nd. COD Ghosts is 14th on PS4 and 39th on Xbox One this year. Last year was dominated by GTA V which sold practically twice the rate of Ghosts on both the PS3 and 360. Also Ghosts got a boost with the £10 upgrade for generation transition which also counted as an extra sale.
These charts are single unit based copies sold to customer whereas what IGN and the rest of the media have been focusing on is copies shipped to retailers where the publisher actually makes their money. Ghosts has sold a lot of late to shops because Activison are offloading their copies for peanuts to wholesale according to the manage of my GAME store. So if Activison ship two trillion copies of COD; that doesn't mean 2,000,000,000,000 have been bought by actual people.
So despite the 'lack of options', more people have bought the exclusives of the next gen leaving COD Ghosts for dust deep down in the charts. Even FIFA and MGS have outsold Ghosts on the PS4. Activison can ship as many copies as they want but at the end of the day; the gamers know what they want and it ain't fucking Ghosts