I have noticed a certain contradiction in that article.
Given that it implies the development of a software by a single programmer, otherwise development times indicated do not make sense:
Simple app = 300 hours
min. charge per hour (Android) = India (min $8 - avg. $26)
Then a simple app, develop in India for $8/h, will cost: min. 300x8 = $2,400, avg. 300x26 = $7,800
"The cost varies... A small app costs $3,000-$8,000". Where? In India only.
Also, I don't believe there are 1.6 millions Android apps and 1.5 millions IOS apps; I think the gap is larger (and... where? In "official" markets only, I suppose).