What about Blendle? They had NYT, WaPo and WSJ as launch partners in 2014 but give up on micropayments in 2023 citing "very low demand"
Or Flattr. Or Invisibly. Or Pico. Or Brave's goofy crypto token. Or Coil. The Washington Post themselves experimented with cheap "day passes" a few years ago but I guess they didn't work well enough to keep. Arguably Medium's rev share program was another failed attempt. Heck no less a content middleman powerhouse than Apple tried and mostly failed to do a rev share / micropayments scheme with Apple News.