Earlier quoted context omitted.
Advertisements are not the reason they're in decline. People don't sign up for Netflix because it's ad-free, they sign-up for convenience.
And yet Hulu+, with more timely content is doing no where near as well as Netflix. Hint: One of those services has ads.
Bonus Hint: One of those services was released to game consoles and Roku in 2008 while the other was added late 2010, early 2011.