The athletic hasn't made a dime. They've simply secured funding which doesn't really mean much.
In addition the list of paywall failures like the nytimes is very long.
https://qz.com/1173033/the-psychology-behind-why-journalism-paywalls-still-dont-work/
https://www.techdirt.com/articles/20180506/11501539779/medias-paywall-obsession-will-end-disaster-most.shtml
https://om.co/2018/05/04/the-paywall-quandary-how-many-subscriptions-does-one-really-need/?curator=MediaREDEF
Paywalls aren't a magic goldmine. Providing good content and engaging your audience will generally give you a number of possible business strategies that don't involve a paywall. Just throwing existing content behind a paywall is not the panacea many believe it to be...this thread alone shows that most don't find the Buffalo News worth paying for and many, like myself, didn't read it when it was free so now even if they start providing really good content, I can't see it. They're going to have to go out of their way to attract people back into the buffalo news ecosystem...