Earlier quoted context omitted.
This is mathematically simple to fix. Charge US$0.50 per month ($6 per year) for every domain reservation regardless of who is reserving. The fee must be charged per month and not per year, which intentionally results in greater maintenance overhead. I don't care if you are a registrar, government, charity, school, or whatever. US$0.50 each and every month for each and every name. Registrars can slap whatever markup…
Advertisers often pay 3€ - 5€ to google for one click. If your 100,000 domains are not complete garbage, you should easily get a million out of it.
The auction rate is determined by the winning bid rate of the competing content providers. In the Las Vegas hotel booking example the hotel properties might pay up to $16 for their ad display along side Google search results and up to $24 for a click through. Most ads, though, are rated at pennies. Anything that can achieve bid rates over $0.50 is a gold mine.
So, yes, some providers will pay far more than $7.00 for a click, but that is extraordinarily rare. This is even more rare when source and context are taken into account. Impressions that look organic, like on top of search results, are worth more than those that look like spam. I highly doubt ads that look like spam on a parked domain are doing more than pennies, likely fractions of a penny. The commonality of low rates and weak impressions on online advertising is also why Facebook shares aren't worth more than they are given the traffic and dedicated eyeballs that they have.