I've looked into this, since I think there's a massive amount of value being left on the table due to this disconnect. The standard answer is essentially what you're saying, combined with the fact that some advertisers are willing to pay more. A business that sells ad space is going to sell it as expensively as possible, so they don't want the highest bidder to know they're not on my 'approved subjects' list.
A trick I think they're missing though is that I'm a lot more likely to pay for things a better version of myself should want, even more so if I've essentially asked my advertisers to nag me about it. The potential conversion rates are so much higher that I think any network which gets this right is set to blow the competition out of the water.
If the potential conversion rates are indeed higher, then that would have shown up on A/B tests.
The basic advertising infrastructure has been A/B tested to death. And one of the biggest takeaways that is that what people think that they respond to is not what they actually will respond to. One of the next biggest is that people who actually have responded are often completely unaware of what it is that they are responding to.
The underlying reason is simple. A/B testing is very good at teasing out what we respond to before we consciously notice that we are responding. But since that happens before we are conscious of it, we lack awareness of what caused that.
But the simple fact remains. If you think that advertising would work better if they just did things the way that you think that they should, you are almost certainly wrong.
Given that a 'better me' would probably spend less money on frivolities, that's probably the case.
Really though, it's a wasted opportunity. I have childhood ambitions that I'd follow up almost any realistic lead to achieve. I refuse to believe that out of six billion people, not one has created a product that would help me. But nobody in the ad space is even asking for my input.
A trick I think they're missing though is that I'm a lot more likely to pay for things a better version of myself should want, even more so if I've essentially asked my advertisers to nag me about it. The potential conversion rates are so much higher that I think any network which gets this right is set to blow the competition out of the water.