As a consumer, I do feel I'm seeing a net benefit without any price increases - or at least a benefit commensurate with the price increase. I watch one alternative streaming service for a while, then, when another that interests me more comes along, I switch to that one and cancel the old one. So the amount of content available to me is "eventually better" at a price that's currently pretty stable.
You're right, though, part of this is that I don't watch much TV in any form. It's probably less than 2 hours a week. So it really doesn't make much sense for me to subscribe to more than one service at a time. Not that that means we've canceled the Netflix subscription, but it's becoming a perennial discussion topic around our house of late.
Let me turn it around, on you, though: What makes you think that having a really good library of streaming content available on a single service at Netflix's prices is even financially tenable? The last time Netflix had a really great selection was when their prime service was still renting DVDs, so I certainly don't think they've been able to demonstrate that it's possible. And if they can't, who can? As more of a long tail consumer, the One Streaming Service to Rule Them All future looks pretty bleak to me - cheap, sure, but also crappy. You get what you pay for.