Yeah, which is why serving ads only to people who don't have disposable income (so don't pay for this subscription) makes the ads less valuable.

But that doesn't sound right to me. Not all products and services are targeted at people with disposable income.

I think the truth is just that Twitter is trying to have their cake and eat it too. Why cut off advertising and data harvesting if people are willing to pay you just to change some colors and the app icon?