While I love your site, I have to respectfully disagree with much of what you are saying here.
First, I agree on one main point--your site is not a "startup" or even really a "company" at this point. That said, you still very much have a product, and you are actively monetizing it.
But then let's get into this point by point...
You say that your ads are "non-targeted" but that is not at all accurate. Just because you aren't doing anything actively to target it, doesn't mean Google isn't. Google's AdSense network has a TON of targeting on the back-end that is determining what ads to serve. This can be based on the profile of the user, retargeting lists they may be a part of, the category of site Google has you categorized as (possibly health?) etc. Your ads are VERY targeted. That is actually part of the beauty of the AdSense product.
The second point I really take issue with is that you don't seem to think your site falls into the "if you're not paying for it, you're the product" bucket. Or at least that's how I parsed what you wrote there (apologies if I was off on that).
People aren't paying for your product, and so you are making money by serving them ads. By the nature of it, any ad-supported site falls into that bucket. You require more user impressions/eye balls and that is what you are "selling" to advertisers/Google. This is not inherently evil, and I don't think one needs to prey on their users to leverage advertising. That doesn't mean the saying doesn't apply to them though.
Again, I like what you're doing and think the single banner is a tactful approach (although you'd probably make a lot more by recommending sleep/health-related products and using affiliate links). But those two things you said just aren't accurate so I wanted to clarify on those a bit.