Well, let's give credit to the fact that Netflix has a HUGE first-mover advantage and has built up a lot of brand loyalty/force-of-habit with many Americans, especially those under 30. I think they're probably doing a decent job getting the YA and kid audiences invested in their Netflix Originals, which they consume on their phones and tablets (when they're not watching YouTube). And they've had some bona-fide big hits with adults too, including stuff that gets lots of acclaim. (They had the most Emmy noms last year and the second-most behind HBO this year.)
And think about the following: there's not a single streaming device or smart TV that anyone would have that doesn't come with Netflix pre-installed or a couple clicks away. And the Netflix app is also available on (and maybe to an extent systemwide-integrated into) set-top boxes from Comcast, DISH, Verizon, Cox, Altice and TiVo. Lots of device remotes have dedicated Netflix buttons.
I do think that Netflix, in the US at least, is going to get taken down a couple notches over the next couple of years but it's WAY too premature at this point to think that they're destined to be the new MySpace.