Carbon Ads has pretty solid CTR, ads perform, advertisers renew, etc. It's not all doom and gloom for online advertising when you respect users and work hard to combine quality advertisers and publishers.
CTR isn't the only KPI by which ads are sold. These days, publishers understand that ads still influence even if normal users don't actually click. When a purchase is preceded by an impression from my ad network, in some cases I can get credit for a portion of it.
The whole ad business reeks of desperation. However, it does pay the bills, so I guess it actually works.