[jamescostian]

> But the boom for mobile apps will never be over, much like web apps will never be over. How many billion dollar websites emerged a decade after everyone said the web boom was over?

I don't think the author was arguing that there can never be "billion dollar" apps, just that the "boom" is over. Similarly, people still say that the "web boom" ended a very long time ago, but they aren't saying "You cannot make billion dollar websites now that the web boom is over", they are just saying that the boom is over.

Just look at a definition of the word boom to understand it better: "of a business or industry : to grow or expand suddenly" [0]

[0] http://www.merriam-webster.com/dictionary/boom