Major market NPR affiliate developer here. We need ads (digital) and underwriting (OTA) to operate. Member donations are great but don't make up the entire budget.
If you're in a position to suggest, let people donate to NPR to get a version of the app that never shows ads as their reward.
I noticed mine recently started very occasionally showing ads down on the bottom, but surely the ad revenue from delivering them to a single person is smaller than the amount a typical NPR listener will donate (if they donate at all).